The Role of Task Complexity and Dominant Articulatory Routines in the Acquisition of L3 Spanish

Abstract

Many studies in L3 phonetics and phonology have found that language dominance plays an influential role in determining the source of transfer. However, any effect of language dominance is likely dependent on many factors, including task complexity. As complexity increases, learners should be increasingly likely to rely on the more automatic articulatory routines from their dominant language. We tested this hypothesis by examining the production patterns of L1 Mandarin–L2 English–L3 Spanish speakers acquiring the Spanish tap and trill, performing a less complex word-reading task and a more complex sentence reading task. The results of the former were reported in a previous study, revealing that the speakers transferred the L2 English [ɹ] and [ɾ] to some extent when acquiring the Spanish rhotics. We hypothesized that such transfer would be less prevalent in the same speakers performing the sentence reading task. The results revealed some support for the hypothesis. Transfer of L2 [ɾ] decreased in the sentence reading task, as did transfer of L2 [ɾ] (in trill productions). L2 [ɹ] substitutes did not vary with task. The results highlight that transfer from previous languages is partially dependent on task. Future work should establish when and to what extent language dominance influences the source of transfer.

1. Introduction

Third language (L3) phonological acquisition research has primarily focused on establishing whether transfer1 from the first language (L1) or the second language (L2) is more likely (e.g., Wrembel 2010; Kopečková 2014; Patience 2018, 2019; Wrembel et al. 2019; Cabrelli and Pichan 2021). Studies examining crosslinguistic influence (CLI) in multilingual learners have also investigated variables influencing the source of transfer, including L2 and/or L3 proficiency (e.g., Hammarberg and Hammarberg 2005; Wrembel 2010; Chang 2015; Patience 2019; Cal and Sypiańska 2020; Chen and Tian 2021), language distance (Llama et al. 2010; Cabrelli and Pichan 2021), phonological feature (Domene Moreno 2021), and perceptual assimilation (Wrembel et al. 2019). However, little previous work has focused on whether the type of task conditions CLI. In the present study, we focus on the role of task complexity, and investigate to what extent this complexity influences the source and patterns of transfer. Some previous work in L3 production has found evidence that language dominance may play a role in L1 and L2 to L3 transfer (e.g., Pyun 2005; Kopečková 2014; Llama and Cardoso 2018; Patience 2019). Language dominance has a plausible role in L3 transfer, because a speaker’s most dominant articulatory routines are likely to at least partially impact their L3 production. As task complexity increases, speakers are increasingly likely to rely on more automatic articulatory routines, which in sequential learners is generally the L1 (although the tendency to rely on dominant articulatory routines may be dependent on L2 and L3 proficiency, among other factors; see Wrembel 2015 for a summary of factors influencing transfer in L3 acquisition).

We test this hypothesis in 17 L1 Mandarin–L2 English learners of L3 Spanish, a unique language pairing of learners who were tested in Canada while immersed in the L2 (English). We aim to establish whether L2-based transfer decreases as task complexity increases, and whether L3 oral proficiency conditions any association between L2 transfer and task complexity.

The effect of task complexity is examined via both facilitative and non-facilitative L2 transfer. The data come from a larger study in which Spanish learners performed a series of production tasks in their L3 Spanish, including a word reading and sentence reading task, both of which consisted of realizations of the tap and trill in tonic and post-tonic syllables. Participants were also tested on their production of the L1 Mandarin rhotic, L2 English flap, and L2 English /ɹ/ in order to identify possible sources of transfer. The Spanish rhotic production results of the word reading task are reported in Patience (2018); in the present study, we report the results of the sentence reading task and compare the results to those of the word reading task.

Patience (2018) found that participants who had acquired the L2 English flap demonstrated higher accuracy with the L3 Spanish tap, which was interpreted as evidence suggesting facilitative L2 transfer. Our hypothesis predicts that this observed correlation will be less strong, or disappear completely, in the more complex task, given that the learners (all dominant speakers of their L1 Mandarin) should be more likely to rely on L1 articulatory routines. Regarding non-facilitative transfer, we examine L3 Spanish tap and trill production together. Patience (2018) found several patterns in the L3 production of the Spanish rhotics (/ɾ/, /r/): primarily /l/ substitutions, L2 English /ɹ/ substitutions, or a variety of non-target segment types, not clearly attributable to the L1 or L2. Our hypothesis predicts fewer realizations of the L2 English /ɹ/, and more /l/ substitutions, given that /l/ likely reflects the L1 routines of the native Mandarin speakers2. A second type of negative transfer we examine is non-facilitative transfer of the L2 English [ɾ] in L3 trill production. In Patience (2018), some speakers who had acquired the L2 flap, but not the L3 Spanish tap, produced non-target [ɾ] substitutes for the trill, suggesting non-facilitative transfer.

We were also interested in the role of L3 oral proficiency, which was determined according to accentedness ratings performed by native Spanish speaking judges. The least proficient speakers should rely most on automatic articulatory routines. As a result, L2 transfer was expected to be lowest in the least proficient speakers.

All L3 Spanish productions were coded for type of segment produced. We then ran mixed effects models to compare whether the task, and the interaction between task and oral proficiency, had an effect on the assumed source of transfer.

The rest of the paper is organized as follows. We begin by discussing the characteristics of the two Spanish rhotics, in order to highlight the acquisition task of our learners. We also discuss L1 Mandarin and L2 English sounds that could potentially influence any crosslinguistic tendencies observed in the L3 Spanish production. In Section 1.1.2, we briefly review previous work on L3 production and findings related to transfer source. This is followed by a discussion of task effects in non-native speech production. We finish the section by outlining our research questions and predictions. In Section 2, we present the results of the study, focusing first on the correlation between accurate L3 tap and L2 flap production. We then consider non-facilitative transfer of L2 /ɹ/, L2 [ɾ], and L1 /l/. We finish the manuscript with a summary of the results, and a discussion of their implications for research on L3 phonetics and phonology (L3PP).

1.1. Background

1.1.1. Relevant Phonetic and Phonological Characteristics of Spanish, Mandarin, and English

Spanish

There are two rhotic phonemes, the tap /ɾ/ and the trill /r/, in the Spanish consonant inventory. The tap /ɾ/ is a voiced alveolar segment, consisting of a rapid tongue tip to alveolar ridge gesture (Martínez Celdrán and Fernández Planas 2007). The average length of a tap is approximately 23 ms, but in extreme cases it may exceed 30 ms (Blecua Falgueras 2001). Similarly, the articulation of trills involves a rapid, brief contact between the tongue tip and the alveolar ridge (Navarro Thomás 1957), but the primary difference is that trills are realized with multiple closures (generally 2–3, although more is also possible) instead of only one. Therefore, trills have a relatively longer duration, with an average length of 82–88 ms (Quilis 1993) in intervocalic position. One potentially important articulatory difference between the tap and trill, other than those previously noted, is the fact that the tap is realized with a single intentional tongue movement. The initial tongue tip gesture of the trill is also an intentional raising of the tongue tip. However, subsequent closure and opening gestures are the result of an automatic vibration of the tongue due to the Bernoulli effect (Martínez Celdrán and Fernández Planas 2007). Achieving the tongue trilling is often very challenging for learners of Spanish, at least in speakers who do not have trills in the other languages that they speak (e.g., Ortí Mateu 1990; Johnson 2008; Kopečková 2014). Trills are so complex that in some cases, they are not acquired even by native speakers (Solé 2002). As we will see below, the L1 Mandarin–L2 English speakers have no other segments that are similar to the trill, whereas the Spanish tap shares some similarities with both Mandarin and English sounds.

Phonologically, the two Spanish rhotics are contrastive in intervocalic position. Some examples include minimal pairs such as pero /ˈpeɾo/ ‘but’ versus perro /ˈpero/ ‘dog’, and caro /ˈkaɾo/ ‘expensive’ versus carro /ˈkaro/ ‘car’ (Willis and Bradley 2008). Given that the two words from each minimal pair normally consist of different syntactic categories (e.g., pero is a conjunction whereas perro is a noun), a mispronunciation of the Spanish intervocalic rhotic is not likely to cause confusion. It may be for this reason that L2 Spanish learners often produce the same sound for the tap and the trill (Face 2006; Johnson 2008).

Orthographically, the two Spanish rhotics are distinguishable in intervocalic position by their orthography—the tap has a single <r> grapheme whereas the trill is represented by a double <rr>. Aside from intervocalic position, the Spanish rhotics also occur non-contrastively in other word positions. For taps, they occur in syllable onset clusters, or in word-final or syllable-final position (e.g., problema /pɾo.ˈble.ma/ ‘problem’, por /poɾ/ ‘for’ and parte /ˈpaɾ.te/ ‘part’). In contrast, trills are found word-initially or syllable-initially after the consonants /l/ and /n/ (e.g., rata /ˈra.ta/ ‘rat’ and honra /ˈon.ra/ ‘honour’) (Hualde 2014). Unlike intervocalic position in which the tap and the trill are orthographically distinctive, these two segments are both spelled with a single <r> in non-contrastive positions. For example, the tap /ɾ/ in parte /ˈpaɾ.te/ ‘part’ and the trill /r/ in rata /ˈra.ta/ ’rat’ are both represented by <r>. The fact that the rhotics are not distinguished orthographically except in intervocalic position is another potential reason that the tap and trill appear to be perceptually assimilated as one phoneme in early L2 Spanish speakers.

The pronunciation of the two rhotics may vary depending on the dialect of Spanish. In some variations of Peninsular Spanish, the tap may be realized as a lateral or a fricative, or simply with elision in coda position (Samper Pandilla 2011). The trill, on the other hand, could be pronounced as a fricative, an approximant, or with r-coloring (Henriksen and Willis 2010). In Latin America, the two rhotics may be produced as laterals, as approximants, with assibilation, or with a dorsal instead of coronal gesture. There is also some degree of individual variation, depending on idiolectal habits and stylistic differences, as well as speaker differences such as sex (Henriksen 2014). Articulatory complexity also plays a role (Hualde 2014; Patience 2022). While a considerable number of allophones exist for Spanish rhotics, the tap [ɾ] and the trill [r] are still the most dominant variants and are the ones taught in a classroom setting as the standard realization, including in the Spanish program in which the students were registered. We will therefore assume that these are the targets of the learners.

To summarize, the Spanish rhotics /ɾ/ and /r/ are two phonemes with some similarities—(1) they both have an alveolar place of articulation, (2) they both appear in intervocalic position; and (3) they are represented with the same grapheme <r>. Due to these similarities, the learners of Spanish may confuse or perceptually assimilate the two phonemes. In the following sections, we will introduce some segments in English and Mandarin that share similarities with the Spanish rhotics. The shared characteristics across these languages may provide insight on the potential transfer sources observed in the L3 Spanish rhotic productions.

Mandarin

Mandarin Chinese, also abbreviated as Mandarin, has only one rhotic, with an average length of approximately 95 ms (Smith 2010). It has been described as both a retroflex fricative /ʐ/ and a post-alveolar approximant /ɹ̺/. Scholars disagree as to the exact realization of the rhotic. Duanmu (2000) claims that the Mandarin rhotic should be considered an approximant because it has very little frication. Moreover, since Mandarin only has voiceless obstruents, having a single voiced fricative with no other voiced obstruents would be phonologically odd. Lee (1999) also argues that the rhotic is an approximant, based on an articulatory and acoustic study. The author found that the Mandarin rhotic was produced with no frication and had a post-alveolar rather than retroflex articulation. Lee’s study was only based on four speakers, and only word-initial /ɹ̺/ was examined. Therefore, the results shown from this study would not have captured any potential variation of the Mandarin rhotic. Cerini (2013) agrees that the Mandarin rhotic is indeed an approximant because it is the most frequent realization. However, he also acknowledges the existence of the fricative allophone and indicates that either of the two variations (or a hybrid of both) may be pronounced by the speaker. More recent acoustic and ultrasound analyses have revealed that part of the variability is due to the position of the rhotic. Chen and Mok (2019, 2021) found that syllable initial, pre-vocalic rhotics (such as those investigated in the present study) were reliably produced with some initial frication, and, when compared to the English /ɹ/, had a significantly higher F3, revealing that the articulation is less retroflex than in English. The Chen and Mok (2019, 2021) studies included 10 and 18 Mandarin speakers, respectively, and 10 and 16 English speakers, thus the results may be more reliable than those found in Lee (1999). Taken together, previous research on the Mandarin rhotic suggests that in pre-vocalic position, Mandarin rhotics are likely to consist of some frication, and some lowering of F3, but not to the same extent as in English.

Phonologically, the Mandarin rhotic can occur in syllable onset, intervocalic position as in lǎorén /lauɹ̺ən/ ‘old people’ or syllable finally as a syllabic consonant in affixed forms, as in gao-gaor-de [kau-kaɚ-də] ‘rather tall’ (Duanmu 2007). In contrast, the post-alveolar approximant /ɹ̺/ is not present in consonant clusters, since consonant clusters are not allowed in Mandarin.

Due to the variability of the findings reported in the literature, it was important to test the realization of the L1 Mandarin rhotic by the speakers of the present study. Patience (2018) found that the Mandarin speakers in this study produced two main variants (a similar observation to Cerini 2013), an approximant and a fricative, although often, as noted in Chen and Mok (2019, 2021), the approximant variant consisted of some frication. Most of the speakers displayed intra-individual variation, producing both variants. Examples of each variant produced by speakers from the present study are displayed in Figure 1.

Orthographically, the Mandarin rhotic is transcribed with phonetic transparency as <r>. The transcribing system is called Pinyin, a Romanized writing system of Chinese which is taught to Mandarin speakers beginning in elementary school (Duanmu 2007). For children, Pinyin is essential when learning Chinese characters because it accompanies every new character that appears in the textbook as a cue to the pronunciation of that character (Hanley 2005). At the same time, it is also frequently used by both children and adults as a means of typing on electronic devices. Therefore, Mandarin speakers are frequently exposed to Pinyin, which could facilitate orthographic transfer when producing Spanish phonemes. However, since the dominant script of Mandarin is Chinese characters (not Pinyin), L1 Mandarin speakers are relatively less experienced with the Roman writing systems than L1 English speakers. Consequently, the orthographic transfer from Mandarin to Spanish is expected to be less in L1 Mandarin compared to L1 English speaking learners of Spanish, and less from the L1 Mandarin than from the L2 English of the present study’s speakers.

In summary, the Mandarin rhotic /ɹ̺/ and the Spanish tap /ɾ/ and trill /r/ are quite different with respect to both their phonetics and phonology. Phonetically, the Mandarin and Spanish rhotics diverge in terms of the place and manner of articulation; phonologically speaking, although the rhotics in both languages may appear word-initially and word-medially, the Chinese rhotic diverges from its Spanish counterparts because it is not allowed in codas and consonant clusters. In addition, although the rhotics in both Mandarin and Spanish are transcribed as <r> orthographically, the likelihood of orthography contributing to perceptual categorization is expected to be lower for Mandarin learners of Spanish than for L1 English-L2 Spanish learners. The smaller effect of orthorgraphic influence, in addition to the differences between the Spanish and Mandarin rhotics, could explain why no Mandarin [ɹ̺] substitutes were observed in the Spanish word reading task in Patience (2018). Indeed, as previously discussed, Patience (2018) observed primarily /l/ substitutes, which is consistent with the patterns observed in L1 Mandarin–L2 Spanish speakers. For example, Ortí Mateu (1990) found that L1 Mandarin speakers tend to produce the lateral in place of the Spanish tap /ɾ/. Why do the Mandarin speakers transfer /l/ and not some other similar segment? Mandarin speakers find it difficult to discriminate the Spanish tap-lateral contrast (Ortí Mateu 1990; Chih 2013). Accordingly, this substitution pattern is likely largely due to misperception. The phonotactic similarity of /l/ and /ɾ/ may also contribute to the perceptual categorization of /l/ and /ɾ/. Both segments are liquids in Spanish and can occur in initial stop-liquid clusters. The combination of phonetic and phonological similarity could cause learners to perceptually assimilate the two sounds. The same argument is also applicable to English learners of Spanish, yet we do not observe lateral substitutes in L1 English speakers of Spanish. We hypothesize that the difference is likely primarily due to a weaker role of orthographic transfer in Mandarin speakers, as previously discussed.

The other Mandarin segment that should be considered as a possible competitor for substitution is the voiced stop [d], which only occurs allophonically in Mandarin, as an allophone of /t/ in unstressed syllables (Duanmu 2007). Since it shares the same place of articulation and voicing as the Spanish tap, it is a possible source of perceptual assimilation.

The L1 Mandarin participants in this study also spoke English as an L2, thus L2 English segments may function as possible substitutes for the Spanish rhotics. The following section will discuss the most probable candidates in English.

English

The present study’s participants were all living in Canada at the time of testing, and had been exposed more to Canadian English than other dialects. For this reason, we focus the discussion on Canadian English segments.

English has only one rhotic, the voiced retroflex or bunched-tongue approximant /ɹ/ (Ladefoged and Maddieson 1996). The duration of the English rhotic is approximately 95 ms (Smith 2010). Phonologically, it may occur in word-initial, intervocalic, or word-final positions (as in run /ɹʌn/, merry /mɛ.ɹi/ and poor /pɔɹ/, respectively). Additionally, the English /ɹ/ may appear in obstruent-rhotic clusters such as tree /tɹi/ and free /fɹi/. Similar to Spanish, the English rhotic is also transcribed orthographically as either <r> or <rr>. Despite the fact that English /ɹ/ diverges from the Spanish rhotic phonetically, both L1 and L2 English speakers may recognize that the rhotics in Spanish and English appear in similar environments with the same orthography (e.g., <r> and <rr>). Consequently, such similarity between the two languages could result in perceptual categorization of the English and Spanish rhotics.

Aside from /ɹ/, English also has a flap/tap [ɾ] that serves as an allophone of the intervocalic alveolar stops /t d/ when in the onset of an unstressed syllable (e.g., water /wɑtəɹ/ [ˈwɑ.ɾɚ]) (Ladefoged and Maddieson 1996). While it is often described as a flap, in true articulatory terms it is generally a tap like the Spanish /ɾ/. The primary difference between a flap and a tap is that the former is a brief up-down movement of the tongue tip, whereas the flap is a brief back-to-front movement. While the English segment is generally realized as a tap, in some contexts it is realized as a flap, such as in the word ‘thirty’. The rhotic /ɹ/ preceding the /t/ causes the tongue tip to curl back, and it then flicks forward to articulate the flap (Ladefoged and Johnson 2015). Not only is the tap sometimes realized as a flap, but the tap itself is realized with multiple articulatory variants (Derrick and Gick 2011). Throughout this paper, we will refer to the English segment [ɾ] as a flap, partly to distinguish it from the Spanish tap, but also because it has historically been described as such. Nevertheless, it is important to note that English speakers produce multiple variants of a tap-like sound, one of which is identical to the Spanish tap. Due to the existence of the same sound in English, learners who have acquired the English flap could transfer it to Spanish, in a form of facilitative transfer.

In different English-speaking regions, the English rhotic /ɹ/ and the post-tonic /t/ and /d/ may be realized with several variations. For instance, the rhotic /ɹ/ may also be realized as [ʁ] or [ɾ]; the former is a UK variant, and the latter appears in both UK and South African dialects (McMahon 2002). In certain positions, the rhotic may also be realized with elision (Yavas 2016). In the case of the post-tonic alveolar stops, whereas the most common variation in North American English dialects is the flap allophone [ɾ], in Received Pronunciation it is realized as the alveolar stops [t] and [d], or with glottalization as [ʔ] (Wells 1982; Yavas 2016). While the variation of English rhotics is not the central to the present paper, it is worth mentioning because most of the participants first learned English in China. General American is typically the more commonly taught dialect in China and indeed, our speakers reported in their language background questionnaires that their main source of dialect was American. However, in some cases, the participants had British teachers for some of their schooling. Once again, this highlights the importance of testing what the learners produce in their other languages, in order to determine what can be attributed to transfer.

All of the learners had acquired a target-like English /ɹ/ (consistent with the findings of L1 Mandarin learners of L2 English; Chen and Mok 2019, 2021). Accuracy was determined according to a perceptual and auditory analysis of the English productions (see Patience 2018 for details). All speakers produced a typical English retroflex approximant at least 80% of the time in the primary English production task. The high rates of accuracy indicate that it was a potential source of transfer in all speakers.

The learners were less successful acquiring the L2 flap. Two speakers did not produce any flaps, and accuracy rates in the other participants ranged from 10–100% (

Table 1. Percent accuracy realization of the L2 English flap in the word-reading task and the passage-reading task (from Patience 2018).

Participant	% Accuracy
	Word Reading	Passage Reading
M13	0.00	0.00
M16	0.00	0.00
M12	0.10	0.25
M09	0.20	0.25
M10	0.20	0.00
M06	0.30	0.00
M14	0.30	0.25
M21	0.40	0.50
M11	0.50	0.25
M18	0.50	0.50
M20	0.50	0.50
M15	0.60	0.50
M05	0.80	0.75
M07	0.80	1.00
M08	0.80	0.50
M17	0.90	0.75
M19	1.00	0.75

). Examples of the L2 English /ɹ/ and L2 flap [ɾ] produced by native Mandarin speakers from the present study are presented in Figure 2.

Table 2. Comparison of Spanish, Mandarin, and English rhotics (from Patience 2018, p. 9).

Language	Segment	Manner	Place	Voicing	Phonotactics	Orth.	Duration
Spanish	/ɾ/	Tap	Alveolar	Voiced	M, F, C	<r>	23 ms
	/r/	Trill	Alveolar	Voiced	I, M, C	<r>, <rr>	85 ms
English	/ɹ/	Approximant	Retroflex	Voiced	I, M, F, C	<r>, <rr>	95 ms
Mandarin	/ ɹ̺-ʐ/	Fricative/ Approximant	Post-alveolar/ Retroflex	Voiced	I, M, F	<r>	95 ms

below summarizes the Spanish, Mandarin and English rhotics. Based on a comparison of the three languages and the production patterns reported in Patience (2018), we highlight the following points as they relate to patterns we may observe in the sentence reading task. The English rhotic /ɹ/ and the two Spanish rhotics share many similarities in terms of phonotactics and orthography, even though they differ from an acoustic or articulatory perspective. As previously mentioned, all participants had acquired the L2 English /ɹ/, and it is therefore a potential source of transfer for all speakers. While it was not the main non-target segment observed in Patience (2018), L2 English /ɹ/ substitutes did occur and thus could surface in the sentence reading task examined in this paper. Given that the English flap and the Spanish tap are essentially the same segment, acquisition of the English flap could facilitate acquisition of the Spanish tap, as was found in Patience (2018). Other expected sources of transfer, based on the language comparisons, include the voiced alveolar stop /d/, as well as the lateral /l/. These share some characteristics with the Spanish rhotics (place and voicing) and, especially with respect to the /l/, have been observed in the speech of L1 Mandarin–L2 English speakers (Ortí Mateu 1990). Not surprisingly, they were also the most frequently produced non-target segments observed in Patience (2018).

1.1.2. Summary of Research on Transfer Sources in L3 Acquisition

Research on the acquisition of L3PP has primarily focused on what the source of the transfer is—the L1 or the L2 (see Wrembel 2015; Cabrelli Amaro and Wrembel 2016 for reviews). The results of these studies have been somewhat inconsistent. Many studies have found that the L1 is a stronger source of CLI, suggesting that the dominant language may have a privileged status. For example, Kopečková (2014) and Wrembel et al. (2019) both investigated L3 rhotic production (by L1 German-L2 English-L3 Spanish, and L1 Polish-L2 English-L3 German speakers, respectively) and found that L1 rhotic substitutes were much more prevalent than any L2 rhotics. Similar findings were observed for other structures in Pyun (2005) and Llama and Cardoso (2018), among others. While these studies suggest that the L1 is the stronger source of transfer, other work suggests that it is in fact the dominant language, which is not always the L1. For example, when examining L3 acquisition in heritage speakers, both Llama and López-Morelos (2016) and Lloyd-Smith et al. (2017) found that learners transferred from their more dominant language.

Despite the fact that many studies have found that the dominant language plays a role in transfer source, other work has found some support for the L2 being a stronger source of transfer (e.g., Hammarberg and Hammarberg 2005; Llama et al. 2010; Wrembel 2010; Chang 2015), or a mix of transfer from the L1 and the L2 (e.g., Blank and Zimmer 2009; Wrembel 2014; Sypiańska 2016; Domene Moreno 2021). The discrepancies in the results are likely due to confounding variables. In particular, many studies finding primarily L2 transfer were conducted with typologically similar L2/L3 combinations (e.g., Hammarberg and Hammarberg 2005; Wrembel 2010; Chang 2015).

Patience (2018) was unique in that it was one of the few studies in L3PP to include a typologically and phonologically very distant L1. Despite the language distance, the results suggested primarily L1 transfer, but some evidence of L2 transfer was also observed. Recall that the participants were tested on their production of the L1 Mandarin rhotic, the L2 English rhotic, and the L2 English flap. The participants produced primarily lateral substitutions for both the L3 Spanish tap and trill phonemes. These substitutions mirror L1 Mandarin–L2 Spanish speaker patterns and were not observed in the participants’ L2 English, all of which suggest that the L1 Mandarin speakers transferred from their L1 system. Nevertheless, the /l/ phoneme also exists in English, thus it was not possible to rule out the possibility that learners were transferring an L2 sound. Patience (2019) further analyzed the data from the speakers in Patience (2018) and found that the L3 Spanish was heavily accented with L1 Mandarin characteristics (according to native Spanish speakers’ judgements), including in the speakers that were highly proficient with a minimal accent in English, further suggesting L1 transfer. Moreover, despite the fact that the Mandarin learners had all acquired the L2 English /ɹ/, only two speakers consistently transferred that sound. Interestingly, some positive L2 transfer was observed. The L1 Mandarin speakers who had acquired the L2 English flap were more likely to accurately articulate the Spanish tap. While it is difficult to tease apart L2 positive transfer from acquisition, the results suggest facilitative transfer of the L2 English flap. Otherwise, we would have observed a more random pattern with no correlation.

In sum, previous work suggests that the L1/dominant language may in some cases be a more likely source of transfer, but not the only possible source. We work from this hypothesis in the present study. If the L1 is a more likely source of transfer, it is likely due to the entrenched articulatory routines of the speakers. Therefore, while L2 transfer is a possibility, we should expect L2 transfer to be less likely as task complexity increases, and/or as L3 proficiency decreases. This is due to the fact that learners are more likely to rely on automatic articulatory routines as complexity increases, especially if they have a lower proficiency with the target language. We will discuss the details of the present study in Section 3. However, first we will discuss previous work examining the role of task in the acquisition of L3PP.

1.1.3. Task Effects in L3PP

Previous work investigating non-native speech production has generally found that as task complexity increases, target-like realizations decrease (Dickerson 1975; Abd Ghani 1995; Radu 2020; Patience 2022). The non-target realizations are often due to negative transfer of L1 sounds. This suggests that learners rely on their L1 routines if the complexity of the task increases. Research on learners acquiring an L3 performing different tasks is not uncommon; however, such work has not generally focused on the change in transfer source with greater task complexity. For example, Falahati (2015) and Gut (2010) both examined L3 production by speakers performing multiple tasks. However, their analysis did not consider in detail any change in transfer source associated with task complexity. Kopečková (2014) is one of the few studies conducted at the segmental level of analysis that reports on L1 versus L2 transfer varying across tasks. She examined the acquisition of the L3 Spanish /r/ by L1 German-L2 English speakers. Participants performed five tasks: three picture naming tasks, with the first including auditory and orthographic information in addition to the picture, the second one including the auditory prompt, and the third, only the picture; a reading task; and a free speech task. In terms of complexity, the free speech task would be the most complex, whereas the picture naming tasks should be the least difficult. Interestingly, the rates of L1 transfer were highest in both the free speech task and the picture naming task with the auditory prompt and the orthographic input (i.e., the most and least difficult tasks), although differences across tasks were not significant. Note, however, that very little L2 transfer was observed at all in the speakers, thus it is difficult to interpret any specific role of task.

Hammarberg and Hammarberg (2005) also investigated L3 transfer across three tasks, by a native English speaker who was highly proficient in L2 German, and was learning Swedish. She was recorded performing a picture narration task, a reading task, and a read-after-me repetition task, a few days after her arrival in Sweden. The learner’s performance on the picture narration task was also recorded a second time one year later. With respect to task differences at initial arrival in Sweden, the authors observed primarily L2 German influence in the picture narration task and the reading task, and more L1 English but with some German when performing the repetition task. It is difficult to interpret these results. The authors inform us that the speaker, in the initial stages of learning, specifically attempted to avoid sounding like a native English-speaking learner of Swedish. Given that she had literally just arrived in Sweden, one has to wonder how the participant even managed to perform a picture narration task. The authors do not specify if the learner had any previous knowledge of Swedish. Therefore, we assume she did not, which would suggest that she would have likely relied entirely on a single previously acquired sound system to speak Swedish in those initial stages (the language being German, given that she did not want to sound English). From this perspective, we might consider the picture narration and the reading task to be the least complex, given that the learner was essentially speaking German while performing the tasks. The repetition task consisted of the same sentences from the reading task, but they were repeated by the speaker after listening to the sentences read by a native Swedish speaker, a few words at a time. This task was likely more complex given that the learner now had to attempt to follow a model. While performing this task, the learner sounded more like an English speaker. These results arguably suggest that transfer is more likely from the dominant language with greater task difficulty, if we consider that the repetition task was the more difficult one in this context. It is worth noting as well that English was also more prevalent in the participant’s productions in the picture narration task when it was completed one year after living in Sweden, which further confirms that initially the speaker may essentially have been speaking German and not Swedish—with some Swedish experience, the more dominant English became more prevalent. Additionally, it is important to note here that when speaking in her L2 German, the speaker sounded like a native German speaker to two other native German speakers who listened to her recordings. This indicates that the learner had a very high proficiency in her L2 German. We should therefore expect any language dominance effects to be small (see discussion in Section 4.3 for conditions that are expected to reveal the largest effect of dominant articulatory routines).

Given the dearth of studies examining the role of task effects in L3 production and the unclear results reported in those studies that have examined task effects, our goal with the present study is to provide new data investigating whether task type has an effect on transfer patterns. We discuss the questions that guided our study in the next section.

1.2. Current Study

The present paper aims to answer the following questions, which are presented with their corresponding hypotheses:

Research Question 1 (RQ1).

Does L2-based transfer decrease as task complexity increases?

We address this question by examining both facilitative and non-facilitative transfer. In the word reading task presented in Patience (2018), speakers who were able to produce the L2 English flap were also generally better at producing the L3 Spanish tap. Our hypothesis predicts that this correlation will either be less strong in the more complex task or disappear completely.

Hypothesis 1 (H1).

The correlation between the L2 English flap and L3 Spanish tap productions will be smaller in the more complex L3 task.

Some clear non-facilitative L2 English [ɹ] transfer was observed in the word reading task in Patience (2018). Given that learners are expected to rely more on dominant articulatory routines, less L2 transfer is expected. We therefore expect non-target L2 [ɹ] productions to decrease.

Hypothesis 2 (H2).

Learners will produce fewer L2 English [ɹ] productions in the more complex task.

Research on the acquisition of the Spanish trill has revealed that speakers tend to produce the tap instead of the trill (e.g., Face 2006; Johnson 2008; Patience 2022). We will examine whether learners who produce [ɾ] substitutes for the L3 Spanish trill have acquired the L2 English [ɾ] but not the L3 Spanish [ɾ]. This pattern would strongly suggest that learners are transferring from their L2 English.

Hypothesis 3 (H3).

Negative transfer of the L2 flap for the trill will decrease in the more complex task.

Research Question 2 (RQ2).

Does L3 oral proficiency moderate any association between L2 transfer and task complexity?

As predicted in H2/H3, the more complex task should result in less L2 transfer (and more L1 transfer). However, any decrease in L2 transfer between the two tasks should be moderated by L3 oral proficiency. The least proficient speakers are expected to display the largest decrease in L2 transfer in the more complex sentence reading task.

Hypothesis 4 (H4).

The predicted decrease in L2 transfer in the sentence reading task will be largest in the least proficient speakers. As L3 oral proficiency increases, any differences in L2 transfer across tasks should decrease.

2. Materials and Methods

2.1. Participants

Seventeen L1 Mandarin–L2 English–L3 Spanish speakers participated in this study3. Each participant was recruited either through posters or advertisements that were posted on the Spanish course websites at a major university. Before attending the experiment, participants were asked to complete a language background questionnaire in order to ensure that they met the following three criteria: (1) The participants were L1 Mandarin speakers; (2) They had acquired English educationally as a second language at school in China. Heritage speakers were excluded from the study; and (3) They were enrolled in a university-level Spanish course or had recently completed courses that were at least equivalent to the first-year introductory Spanish course at the university level.

While a majority of the participants were in the process of completing either first- or second-year Spanish courses, six of them had already completed at least six semesters of Spanish courses. More upper-year (third- or fourth-year) Spanish students would have been desirable, in order to better establish changes in transfer patterns as learners become more advanced. However, this was not possible due to a lack of upper students who also met all three requirements.

The average age of the 17 participants was 20 years old. They all indicated that the language they felt most comfortable speaking was Mandarin. All speakers used Mandarin on a daily basis, although the percent English compared to Mandarin use varied across individuals. With respect to their L2 English, most of the 17 participants began learning English in Grade 1 of elementary school (approximately seven years old). However, full immersion in English did not occur until approximately the age of 15 (the average age at which the participants moved to an English-speaking country). While the type of education and years of exposure to English were similar across participants, the level of L2 English oral proficiency varied to some extent (see

Table 3. Summary of L1 Mandarin–L2 English–L3 Spanish speaker participant profiles.

L2 English			L3 Spanish
AoA	LoR	% Daily Eng Use	AoA	LoR	SPA Instruction
7	4	50	18	N/A	3

Notes: AoA = Age of onset of acquisition (first exposure to the language, in years); LoR = Length of residence in an English (left) or Spanish (right) speaking country (in years). % Daily Eng Use = how much L2 English is used compared to L1 Mandarin at work, home, school, and at work (expressed as a %). SPA instruction = number of semesters of undergraduate Spanish instruction.

for a summary of the speaker characteristics; for detailed information about individual proficiency ratings and other individual speaker characteristics, see Appendix A,

Table A1. L1 Mandarin–L2 English–L3 Spanish speaker characteristics.

Participant	Age	L2 English					L3 Spanish
		AoA	AoUse	LoR	Oral Prof	% Daily Eng Use	AoA	SPA Instruction	Oral Prof
M05	22	7	18	4	2.5	64	19	1.5	1.8
M06	20	7	17	3	2.3	44	19	1.5	1.6
M07	19	10	15	4	3.3	35	18	1.5	1.6
M08	19	5	15	4	3.4	37	18	1.5	1.4
M09	17	7	16	1	3.1	38	18	1.5	1.5
M10	19	6	17	2	2.6	35	18	1.5	1.3
M11	21	13	13	8	2.7	70	20	1.5	2.5
M12	21	6	17	4	2.1	50	19	1.5	1.1
M13	19	9	15	4	1.6	31	19	1.5	1.0
M14	19	10	16	3	2.4	53	18	1.5	1.2
M15	19	6	16	3	3.3	83	16	1.5	1.4
M16	20	6	15	5	2.8	43	19	2	1.3
M17	22	7	16	4	3.3	75	18	10	2.8
M18	20	6	10	10	2.6	75	14	8	2.0
M19	21	6	14	7	2.6	40	15	10	1.5
M20	20	5	15	5	3.0	42	16	8	2.0
M21	18	6	15	3	1.9	33	17	1.5	1.0
Average	20	7	15	4	2.7	50	18	3	1.6

Notes: AoA = Age of onset of acquisition (first exposure to the language, in years); AoUse = Age of onset of use (age, in years, when use of the target language began in an immersion setting). LoR = Length of residence in an English-speaking country (in years). % Daily Eng Use = how much L2 English is used compared to L1 Mandarin at work, home, school, and at work (expressed as a %). SPA instruction = number of semesters of undergraduate Spanish instruction. Oral Prof = oral proficiency, determined according to accentedness ratings based on a scale from 1 (strong foreign accent) to 5 (clearly native speaker, no foreign accent).

).

Foreign accentedness ratings were used to determine the L2 and L3 oral proficiency of the speakers. This is a frequently used method for assessing the oral proficiency of a non-native speaker (e.g., Colantoni and Steele 2008; Kopečková 2016; Lloyd-Smith et al. 2017; Patience 2022). They are arguably the most relevant measure of a speakers’ oral proficiency, given that they specifically target the speech motor skill ability of the participants, and are not based on other linguistic domains such as syntax, morphology, or lexicon (Colantoni et al. 2015). To establish the accentedness ratings, all participants were requested to read both Spanish and English versions of the short story ‘The North Wind and the Sun’. All the readings were recorded and presented in randomized order to native speakers. For the Spanish recordings, 10 native Spanish speakers had to listen to and rank their perceived degree of foreign accentedness of the speaker on a scale from 1 to 5 (1 = strong foreign accent; 5 = clearly a native speaker, no foreign accent). Each speaker’s overall oral proficiency was determined by averaging the individual scores provided by the judges. The L3 Spanish oral proficiency scores ranged from 1.0 to 2.8 (M = 1.6). The same procedure was repeated for the L2 English recordings, which were rated by 10 native English-speaking judges. The average L2 English oral proficiency was 2.7 (range: 1.6–3.4). The fact that no speaker had above a 3.4 rating was consistent with the participants’ claims that they were dominant speakers of Mandarin as opposed to English.

2.2. Experimental Tasks and Stimuli

The participants performed a series of tasks in Spanish, English, and Mandarin. The English and Mandarin tasks were included to determine whether the speakers had acquired the L2 English flap and /ɹ/, and to establish what the characteristics of the Mandarin rhotic were for each speaker. As mentioned in Section 1.1.1, all speakers had acquired the L2 English /ɹ/, whereas the acquisition of the L2 flap was highly variable (Table 1). For the details of the methodology of the English and Mandarin productions, see Patience (2018). We focus here on the Spanish tasks, given that the sentence reading task was not discussed in Patience (2018).

In the Spanish word reading task, the participants had to produce words that appeared individually on a computer screen. The orthographic form of the target words (e.g., perro) were presented one word at a time. The experimenter was responsible for controlling the slides to ensure every page was advanced at a steady pace. The task consisted of 24 target stimuli, which were divided into four subcategories with six stimuli in each category, varying by stress (tonic versus post-tonic) and type of rhotic (tap versus trill) (see Appendix A,

Table A2. Spanish stimuli for the word reading task and sentence reading task.

Tap /ɾ/
Tonic			Post-tonic
morí	/moˈɾi/	‘I died’	caro	/ˈkaɾo/	‘expensive’
veré	/beˈɾe/	‘I will see’	pero	/ˈpeɾo/	‘but’
lloré	/joˈɾe/	‘I cried’	hora	/ˈoɾa/	‘hour’
herido	/eˈɾido/	‘hurt’	cero	/ˈθeɾo/	‘zero’
verano	/beˈɾano/	‘summer’	era	/ˈeɾa/	‘it was’
marido	/maˈɾido/	‘husband’	pare	/ˈpaɾe/	‘stop’
Trill /r/
Tonic			Post-tonic
corrí	/koˈri/	‘I ran’	carro	/ˈkaro/	‘car’
cerré	/θeˈre/	‘I closed’	perro	/ˈpero/	‘dog’
borré	/boˈre/	‘I erased’	corra	/ˈkora/	‘it runs’
derrito	/deˈrito/	‘I melt’	cierro	/ˈθjero/	‘I close’
cerrado	/θeˈrado/	‘closed’	guerra	/ˈɡera/	‘war’
arriba	/aˈriba/	‘up’	barre	/ˈbare/	‘sweep’

for the full set of stimuli).

Table 4. Example stimuli from each of the four conditions in the word reading task.

Context	Tap	Trill
Tonic	veré /be.ˈɾe/ ‘I will see’	corrí /ko.ˈri/ ‘I ran’
Post-tonic	pero /ˈpe.ɾo/ ‘but’	carro /ˈka.ro/ ‘car’

below provides one example for each of the four combinations. Each of these stimuli were frequent beginner-level Spanish words and were carefully chosen based on the first-year Spanish textbook used by the University and a Spanish word frequency dictionary (Davies 2006). Thirty-eight distractor stimuli were also included. The word list was designed to be read twice by each participant, which led to a total of 48 rhotic tokens per speaker.

The sentence reading task was designed to create a corpus of L3 Spanish production by L1 Mandarin speakers, in order to examine their production patterns on a variety of segments. We only report here on the stimuli included to test the present study’s research questions (i.e., the tap and trill stimuli). The task consisted of a total of 25 sentences, eliciting 13 intervocalic Spanish taps (7 tonic, 6 post-tonic), and 11 intervocalic trills (6 tonic, 5 post-tonic). The words with the rhotics were in most cases identical to the words in the word reading task. Example sentences and the target segments elicited are displayed in Appendix A (

Table A3. Spanish stimuli for the sentence reading task.

Tap Stimuli
Sentence	Target	Word	IPA	Translation	Stress
Es una tela muy cara.	/ɾ/	cara	/ˈkaɾa/	‘expensive’	post-tonic
Te borré de mis sueños y empecé de cero.	/ɾ/	cero	/ˈθeɾo/	‘zero’	post-tonic
Era malo pero inteligente.	/ɾ/	era	/ˈeɾa/	‘it was’	post-tonic
¿A qué hora es la boda?	/ɾ/	hora	/ˈoɾa/	‘hour’	post-tonic
¡Necesito que pare la lluvia!	/ɾ/	pare	/ˈpaɾe/	stop’	post-tonic
Era malo pero inteligente.	/ɾ/	pero	/ˈpeɾo/	‘but’	post-tonic
Hoy pelé cuarenta cebollas y olí a cebolla todo el día!	/ɾ/	cuarenta	/kwaˈɾenta/	‘fourty’	tonic
Mi dedo está herido.	/ɾ/	herido	/eˈɾido/	‘hurt’	tonic
Lloré cuando supe de la guerra en Chile.	/ɾ/	lloré	/joˈɾe/	‘I cried’	tonic
Mi marido ya no tiene pelo.	/ɾ/	marido	/maˈɾido/	‘husband’	tonic
Me morí de emoción cuando vi a mi perro.	/ɾ/	morí	/moˈɾi/	‘I died’	tonic
Este verano, voy en carro a Boston.	/ɾ/	verano	/beˈɾano/	‘summer’	tonic
Te veré de nuevo en dos días	/ɾ/	veré	/beˈɾe/	‘I will see’	tonic
Trill Stimuli
Sentence	Target	Word	IPA	Translation	Stress
Mi hijo barre la cocina todos los jueves.	/r/	barre	/baˈre/	‘erases’	post-tonic
Este verano, voy en carro a Boston.	/r/	carro	/ˈkaro/	‘car’	post-tonic
Dudo que corra más lento que mi marido.	/r/	corra	/ˈkora/	‘it runs’	post-tonic
Lloré cuando supe de la guerra en Chile.	/r/	guerra	/ˈɡera/	‘war’	post-tonic
Me morí de emoción cuando vi a mi perro.	/r/	perro	/ˈpero/	‘dog’	post-tonic
Al mediodía el sol está arriba en el cielo.	/r/	arriba	/aˈriba/	‘up’	tonic
Te borré de mis sueños y empecé de cero.	/r/	borré	/boˈre/	‘I erased’	tonic
La piscina estuvo cerrada esta mañana.	/r/	cerrada	/θeˈrada/	‘closed’	tonic
Cerré la casa con llave.	/r/	cerré	/θeˈre/	‘I closed’	tonic
Este otoño, corrí todos los días en la playa.	/r/	corrí	/koˈri/	‘I ran’	tonic
Come tu helado antes de que se derrita.	/r/	derrita	/deˈrita/	‘it melts’	tonic

Note: Some sentences had more than one stimulus, and for this reason are listed twice in the table. However, each sentence was only produced once by each participant.

). As with the word reading task, this task was presented to participants orthographically, one sentence at a time.

2.3. Procedure

Upon arrival, the participants completed a language background questionnaire. The questions focused on obtaining information about the languages spoken by the learners and the extent of their experience with the different languages, in addition to general speaker characteristics. After completing the language background questionnaire, the participants performed all of the Spanish tasks. The sentence task preceded the word reading task, due to its greater complexity. For this reason, it was preferable to finish with the word reading task, when participants may have begun to tire. It is also for this reason that the tasks consisting of the participants’ more proficient languages (English, Mandarin) came after the Spanish production tasks. When performing the sentence reading task, the participants were asked to first silently read through the sentence, before producing it out loud when ready.

2.4. Data Preparation and Analysis

All productions were analyzed in Praat (Boersma and Weenik 2016). Each production was labelled with the segment that was produced, determined using both acoustic and auditory information (Figure 3). The speakers labelling the sounds were the authors of this paper; a native English, near-native Spanish speaker, with expertise in English and Spanish phonetics. The second author is a native Chinese, near-native English speaker, also proficient in Spanish, and trained in phonetic analysis. Both authors coded all segments; coding discrepancies, which were rare, were solved by consulting with a third person, a native Spanish speaker, and near-native English speaker.

We used a binary coding system given that there was no single acoustic feature that could effectively identify the large variety of non-target variants we expected to observe. In this sense, the analysis of rhotic production is quite different from that of vowels, voicing, or VOT. For example, we could have examined the height of F3 in order to potentially identify any productions of [ɹ], yet this would not be sufficient to identify [l] or [d]. Moreover, a full acoustic analysis was unnecessary to determine the segment type produced, given that the productions were generally not difficult to accurately label. A binary analysis consisting of identifying the segment type produced allowed us to effectively establish the source of transfer (i.e., an [ɹ] substitute reflects L2 transfer). Nevertheless, the limitation of a binary coding system is that we may have missed some subtle phonetic markers which could have originated from either the L1 or the L2. For example, it is plausible that some [l] substitutions were produced with a slight decrease in F3 indicating some influence from [ɹ]. In future work, the results of the present study could be combined with an acoustic analysis to establish whether there were perhaps some unexpected sources of CLI from the L1 or the L2.

2.5. Statistical Analysis

A total of 1222 tokens were analyzed (73 per speaker × 17 speakers). Nineteen tokens were excluded from the statistical analysis, due to sound quality issues (e.g., background noise, laughing, mumbling) or participant production errors. All statistics were run using R version 4.0.0. Mixed effects models were run using the lmer (Bates et al. 2015) and lmerTest (Kuznetsova et al. 2017) packages. In all cases, the models included random intercepts for participant and word. Significance was determined based on p-values below .05. Note that while we controlled for potential differences in tonic and post-tonic syllables by including stimuli in both contexts, Patience (2018) found no effect of stress on the L3 Spanish productions. For this reason, we did not include stress as a predictor variable in our analysis.

3. Results

We begin by summarizing the general trends observed in our data. Figure 4 displays the proportion of each segment type produced by task, for the tap target.

A target [ɾ] was the most frequent realization in the word reading task (36% of all realizations in the word reading task), followed by [l] (33%), and [ɹ] (14%). The final 17% consisted of [dɾ], [d], and several other realizations (e.g., [dl, ɾd, f]), categorized as other due to the low rates of occurrence. In the right portion of the graph, we can see that the sentence reading task had similar proportions of realizations. [l] was most common, realized in 38% of productions, followed by target taps (24%), [ɹ] (14%), and [d] (11%). The remaining 13% consisted of a variety of other segment types (e.g., [lh, n, ð, ∅]).

The results for the trill target are displayed in Figure 5. As with the tap results, they are grouped by task, with the word reading task on the left, and the sentence reading task on the right.

Target trills were uncommon, with only 12% and 10% of productions being realized as [r] in the word and sentence readings tasks, respectively. In the word reading task, the most frequently observed non-target segment was /l/ (26% of realizations), followed by [ɾ] (20%), [dɾ] (18%), [ɹ] (12%) and a variety of other segments (e.g., [d, ð̞, r̞]), none of which occurred with any frequency. In the sentence reading task, non-target realizations consisted of [l] (32%), [ɹ] (13%), [d] (13%), [ɾ] (11%), [dɾ] (9%), and several other types of segments (e.g., [ð, ð̞, dɾ, dʒ, ʒ]), making up the final 12% of productions.

We turn now to our first RQ, which aimed to examine the role of task on facilitative and non-facilitative L2 transfer. First, we analyze the relationship between the L2 flap and L3 tap accuracy, comparing the strength of the positive association across tasks. The scatterplot in Figure 6 displays the relationship between flap and tap accuracy overall. We can see that in general, as flap accuracy increases, there is also a tendency for the tap accuracy to increase (ρ = .52; p = .032).

Note that four speakers (M09, M11, M18, M20) were more accurate producing the L3 tap than the L2 flap, although M09 had low accuracy with both segments, and generally patterned differently than the other three speakers. Interestingly, M11, M18, and M20 were the most proficient L3 Spanish speakers, with oral proficiencies ranging from 2.0 to 2.5. The results may indicate that the L3 tap is in fact facilitating the acquisition of the L2 flap, although we cannot confirm this with an observation at a single time point—whether this is indeed occurring would need to be confirmed via a developmental study. None of the L2 English speaking characteristics of the four speakers were explanatory here. All four speakers had an average English oral proficiency of 2.6 or higher. M09 had only one year of experience with English in Canada, whereas the three other speakers had five to 10 years of experience. The lesser experience of M09 could potentially explain why the L2 flap accuracy of this speaker was much lower than the other three speakers.

Figure 7 displays the same data, grouped by task. H1 predicted that the correlation of the sentence reading task would be weaker, or disappear altogether. In the word reading task, a significant correlation was found (ρ = .55; p = .021); this correlation was no longer significant in the sentence reading task (ρ = .45; p = .07), supporting the prediction.

In order to further test this relationship and control for potential variability related to individual speaker or item differences, we ran a mixed effects binomial logistic regression with a random intercept for participant and item. The model tested whether the predictors L2 flap accuracy, task, and their interaction had an effect on the target-like realization of the L3 Spanish tap. The results revealed only an interaction between flap accuracy and task; the flap accuracy had a stronger effect in the word reading task (β = 3.01; SE = 0.93; z = 3.24; p = .001). A simple slopes analysis on the regression model confirmed that the regression line was only significantly different from ‘0’ in the word reading task (β = 4.95; SE = 1.54; z = 3.22; p = < .001), and not the sentence reading task (β = 2.55; SE = 1.61; z = 1.58; p = .110). Again, these results support the prediction put forth in H1.

The second research question of interest was whether any influence of task on the transfer source varied with L3 oral proficiency. As discussed in Section 1.2, we hypothesized that L3 proficiency could moderate task effects observed for both positive and negative transfer. Our first analysis examines the effect of L3 proficiency on target-like tap production. In our previous analysis, facilitative transfer of the L2 flap was only observed in the word reading task. We hypothesized (H4) that as L3 proficiency increases, the effect of task complexity should decrease/disappear. We ran the same mixed effects binomial logistic regression as in the previous analysis. However, this model also included L3 proficiency as a predictor, in addition to a three-way L2 flap accuracy, task, and L3 proficiency interaction. The results, displayed in

Table 5. Mixed effects binomial logistic regression examining the effect of the predictors L2 flap accuracy, L3 Spanish proficiency, and task on the outcome variable ‘tap accuracy’.

Fixed Effects	β	SE	z	p
Intercept	−12.50	3.42	−3.66	<.001	***
Flap Accuracy	9.26	5.28	1.75	.080
L3 Proficiency	6.04	2.29	2.63	.008	**
Task: Word	−3.74	2.14	−1.75	.080
Flap Accuracy*L3 Proficiency	−5.96	3.32	−1.79	.073
Flap Accuracy*Task: Word	7.18	3.30	2.18	.030	*
L3 proficiency*Task: Word	2.02	1.27	1.59	.112
Flap Accuracy*Task: Word*L3 Proficiency	−2.63	1.87	−1.41	.159

Notes: * = p < .05; ** = p < .01; *** = p < .001.

, did not reveal a three-way interaction, counter to H4, indicating that L3 proficiency did not likely have an effect on any differences in facilitative transfer of the L2 English flap across tasks.

The second analysis addressing RQ1 consisted of examining whether the frequency with which L2 [ɹ] substitutions occurred varied as a function of task. All speakers had fully acquired the L2 English [ɹ], thus had the ability to transfer [ɹ], and indeed, in Patience (2018), L2 [ɹ] substitutions were observed. H2 predicted that L2 transfer would be less frequent in the more complex task. To test this prediction, we ran an additional mixed effects model, examining the effect of task on the occurrence of non-facilitative transfer in the form of L2 [ɹ] substitutes. [ɹ] was realized in 13% of all productions in the word reading task and in 14% of all productions in the sentence reading task. This difference was not statistically different (β = −0.41; SE = 0.51; z = −0.81; p = .419).

In order to further evaluate H4 (i.e., the role of L3 proficiency), we ran an additional mixed effects model to determine whether the absence of task differences observed in the previous analysis would vary as a function of L3 proficiency. This model was identical to the previous mixed effects binomial logistic regression, but also included L3 proficiency as a predictor and an interaction between proficiency and task. Counter to our prediction, the results, presented in

Table 6. Mixed effects binomial logistic regression examining the effect of the predictors task and L3 Spanish proficiency on the occurrence of L2 transfer.

Fixed Effects	β	SE	z	p
Intercept	1.06	4.71	0.23	.822
Task: Word	−0.93	1.55	−0.60	.550
L3 Proficiency	−4.59	2.79	−1.64	.100
L3 Proficiency*Task: Word	0.36	1.05	0.35	.727

, indicate no interaction between L3 proficiency and task.

The final analysis we conducted to address RQ1 was to examine whether any non-facilitative transfer of the L2 flap occurred. H3 predicted that any such transfer would be less likely in the sentence reading task. In order to determine whether any negative transfer of the L2 flap occurred, we identified speakers who had the ability to transfer the L2 English flap (at least 50% accuracy in the English flap production task) and had not acquired the tap (30% or lower accuracy with the tap). Three speakers matched this criterion (M07, M08, M19). Of these three speakers, only two produced L2 flap substitutes for the trill target. The proportion of flap substitutes in the word reading task was 31% of realizations, whereas in the sentence reading task, this number dropped to 9% (one speaker only produced taps in the word reading task). The results support the hypothesis, although the evidence is weak due to the small number of speakers and tokens.

While the results reveal that L2 [ɹ] substitutions are no less frequent in the more complex task, one question that arises is whether presumed L1 transfer increases in the word reading task. If L1 transfer increases, we should observe additional non-target [l] substitutions. A mixed effects binomial logistic regression revealed that /l/ substitutions were 1.7 times more likely in the word compared to sentence reading task (β = 0.54; SE = 0.20; z = 2.68; p = .007). While we cannot guarantee that the [l] substitutions originate from the L1, the /l/ substitutions reflect L1 Mandarin patterns, and are consistent with what we would expect if L1 transfer did indeed increase.

4. Discussion

We begin this section by discussing the results as they relate to our research questions and predictions. We will then address the relevance of the findings with respect to the field of L3 acquisition. We finish by discussing some limitations and future avenues of research.

4.1. Summary of Findings

Our first RQ aimed to determine whether L2-based transfer decreases as task complexity increases. As a consequence of increased complexity, learners are expected to rely on more automatic L1 articulatory routines. We tested this hypothesis in three ways. First, we examined the relationship between L2 flap and L3 tap accuracy in a word reading and a sentence reading task. One of the findings in Patience (2018) was that the acquisition of the L2 flap facilitated production of the L3 tap. We therefore predicted that this correlation would be smaller or disappear altogether in the sentence reading task. The results supported this prediction. A significant correlation between the flap and tap accuracy was only observed in the word reading task. This correlation was no longer present in the sentence reading task, indicating that learners were no longer more likely to produce L3 taps as their proficiency with the flaps increased. This finding confirmed our hypothesis that positive L2 transfer would decrease in the more complex task.

The second analysis we performed to address RQ1 was to determine whether non-facilitative transfer of the L2 English [ɹ] varied with the type of task. All of the participants had acquired the L2 [ɹ], thus it was a possible segment that could be transferred from the participants’ L2. Any [ɹ] realizations would therefore reflect unambiguous L2 transfer. In contrast to the flap results, L2 [ɹ] substitutions did not decrease in the more complex task, counter to our second hypothesis.

A third analysis consisted of identifying whether differences were observed in non-facilitative transfer of the L2 flap for the L3 trill target. While speakers with high L2 flap accuracy rates generally were able to produce L3 taps, some speakers who could produce the English flap did not produce Spanish taps. Nevertheless, these speakers did produce [ɾ] substitutes for the target trill. Given that they had acquired the L2 English flap, but not the L3 Spanish tap, the only possible source of transfer would be the L2 flap. We found that the negative L2 flap transfer was observed almost exclusively in the word reading task, as our hypothesis would predict.

A fourth way in which we addressed RQ1, indirectly, was by analyzing whether /l/ substitutions were more common in the more complex task. While this was not specifically included in our research questions, our hypothesis predicts less L2 transfer, and in turn more L1 transfer, as task complexity increases. L1 Mandarin–L2 Spanish speakers frequently transfer the lateral from their L1. As a result, /l/ substitutions were assumed to reflect L1 articulatory routines. /l/ substitutions did indeed increase in the more complex task. Given that /l/ exists in English and Mandarin, the increase in /l/ substitutions only provides weak evidence in support of greater L1 transfer as task complexity increases. Nevertheless, when combined with the analyses examining positive and negative transfer of the L2 flap, the results partially support the prediction that L2 transfer will decrease and L1 transfer will increase, with greater complexity. Why was this same pattern not observed with the L2 English /ɹ/? The L2 productions of /ɹ/ are an unambiguous source of L2 transfer, yet their rate of occurrence was very similar across tasks (13–14% occurrence in both tasks). One possibility is that the task was not complex enough to have an effect on the L2 /ɹ/ realizations. Our L2 English data suggest that /ɹ/ is not a difficult segment for Mandarin speakers to acquire (see also Chen and Mok 2019, 2021). It could be that the high degree of competence with the English rhotic makes it somewhat resistant to the expected effect of greater task complexity. In contrast, the English flap was much more challenging for the Mandarin learners. It is possible that the learners were less competent with the L2 flap, and therefore the task complexity had a greater effect on their ability to realize it accurately. It is also important to note that only four of the participants produced five or more realizations of /ɹ/ in their L3 Spanish, and two of the four produced the large majority. We may not have observed an effect simply because the segment was not prevalent enough in the speech of the participants.

The second research question aimed to establish whether the L3 Spanish oral proficiency moderated any effect of task complexity on L2 transfer. Less proficient learners should have a greater need to fall back on automatic/dominant articulatory routines, especially when performing a complex task. L2 transfer should thus be less likely as L3 oral proficiency decreases, especially in the more complex sentence reading task. We addressed this hypothesis via two analyses. The first consisted of determining whether the task effect observed on the positive correlation of L2 flap and L3 tap accuracy was moderated by L3 oral proficiency. This was not found to be the case. The second analysis examined whether the interaction of L3 oral proficiency and task had an effect on L2 transfer of English /ɹ/. Again, no support was found for the hypothesis. Why was there no combined effect of L3 proficiency and task? One possibility is that the learners were not yet advanced enough in their L3 Spanish to no longer need to rely on L1 articulatory routines. The four most proficient Spanish speakers had accent ratings of 2, 2, 2.4, and 2.8 out of 5, with ‘5’ indicating a speaker with a native sounding accent, and ‘1’ indicating a speaker with a strong foreign accent. It could simply be that speakers need to achieve a higher degree of proficiency before they demonstrate substantial differences in their transfer patterns. A second possibility is that the task complexity may need to be even larger to observe any effect of L3 proficiency. A reading task increases complexity because it requires learners to realize a greater number of articulatory gestures, with each sequence of gestures lasting for a longer period of time than a simple word reading task. Moreover, learners are less likely to focus on form when compared to the word reading task. Nevertheless, a reading task is not cognitively demanding, because learners do not have to think of what to say. It could be that oral proficiency is more likely to be a factor when learners perform a more cognitively demanding task, in addition to increased articulatory complexity. These possibilities will need to be tested in future research.

In sum, the results revealed some evidence supporting the hypothesis that transfer is less likely to originate from the L2 as task complexity increases. We highlight here that the transfer observed reflects transfer of articulatory routines. However, these routines may not always reflect the underlying phonological representation of the speaker. We turn now to the relevance of the findings for research on L3PP.

4.2. Relevance of Findings to the Field of L3PP

The results of the present experiment suggest that in some cases, learners may be more likely to rely on their dominant articulatory routines as task complexity increases. These findings are consistent with previous work observing that dominant articulatory routines can have an effect on the source of transfer observed in L3 production (e.g., Pyun 2005; Llama and López-Morelos 2016; Lloyd-Smith et al. 2017). The results by no means indicate that L1 transfer is the only source. Indeed, as was presented in the word reading task in Patience (2018), and also found in the sentence reading task in the present study, L2 transfer is observed in these speakers. This study simply suggests that task complexity, and likely other types of complexity, can influence the articulatory patterns of the L3 speakers. The implication of these findings is that future studies should interpret their results only in the context of the task they have used, while considering the possibility that different results could be observed depending on the task the speakers performed. Moreover, additional research is required to further explore when and how task complexity will have an effect on the source of transfer. Such work should focus on identifying the extent to which the transfer source varies depending on the degree of complexity of the task.

Given that the L1 is generally the most dominant language in sequential trilinguals, one question that arises is whether the L1 has a privileged status (perhaps due to the fact that it is stored in procedural as opposed to declarative memory, contrasting with the view of the L2 Status Factor Model, Bardel and Falk 2007, 2012) or whether it is simply due to the more automatic articulatory routines of one of a speaker’s languages. Research investigating transfer in heritage speakers acquiring an L3 suggests that it is the dominant routines, and not necessarily the L1 routines, that are the cause of the transfer (Lloyd-Smith et al. 2017). Our results provide further support that language dominance is influential, as opposed to the L1. If the L1 had a privileged status, the task type should not have an effect on the transfer source. We should simply observe primarily L1 transfer overall. The fact that we observed a tendency of less transfer from the less dominant language in the more complex task with respect to the L2 English [ɾ] suggests that the reason that L1 transfer is often observed in L3 production, even when the L1 and L3 are from very different language families, is due, at least in part, to the automatic articulatory routines of learners.

4.3. Towards a Dominant Language Transfer Hypothesis

Why and when might learners transfer from their more dominant language? While many authors have found that either the dominant language or L1 has an effect on the source of transfer (e.g., Ringbom 1987; Hammarberg and Hammarberg 2005; Pyun 2005; Kopečková 2014; Llama and López-Morelos 2016; Lloyd-Smith et al. 2017), it has not yet been formalized with specific predictions in L3PP. Given that language dominance almost certainly plays a role in the transfer source at some and potentially all stages of learning, future work should identify when it is most and least likely to be a factor. The present study’s hypotheses provide some initial predictions. Learners should be more likely to rely on their dominant language with increasing task complexity. However, future work will need to better determine what types of task complexity are most likely to have an effect. For example, spontaneous speech tasks should be the most complex, and thus result in the strongest effect.

Another factor expected to play a role is proficiency. As proposed in the present study, less proficient learners in the L3 should be more likely to rely on dominant articulatory routines. Once the articulatory routines of the L3 become more automatic, dominant routines from the previous languages are likely to be less influential, although recency of use should play a role as well (De Angelis 2007; Wrembel 2015). L2 proficiency is also expected to be highly influential and any effect of L1 language dominance will decrease as L2 (oral) proficiency increases, given that learners may have equally automatic articulatory routines in their L2 that they may default to.

An additional variable that should be considered is the phonetic/phonological structure being investigated. There are many reasons why a learner may transfer structures from their less dominant language. It could be due to awareness of structural similarities between the L2 and L3 (e.g., see Slabakova 2017; Westergaard et al. 2017), or, as proposed in Bardel and Falk (2007), learners may be more likely to transfer from two languages that were learned using the same cognitive processes. We should expect that allophonic processes that the learner is not aware of, and that are more difficult to suppress, are more likely to surface in L3 production as a result of the automatic nature of the processes. Certain segment types are also likely to be more susceptible to automatic articulatory routines. In particular, it has been shown that the vowels from all three of a trilingual’s languages can influence each other (Sypiańska 2016). We therefore expect vowels to be the most likely segment type to be influenced by automatic articulatory routines. Nevertheless, certain articulatory features of consonants which are produced in a gradient manner (e.g., aspiration, voicing) may also be highly susceptible to dominant articulatory routines.

A final factor that we will consider here that is likely to play an important role in moderating any effect of automatic articulatory routines is phonological similarity across the three languages4. The more similar the articulatory gestures are between the L2 and L3, the less influential dominant articulatory routines from the L1 are expected to be, given that the articulatory routines of the L2 are more likely to attract the articulatory routines of the L3 (see Patience (2022) for discussion on the role of attractor states and articulatory routines in non-native speech, in addition to Brannen’s (1996) model of articulatory routines).

Based on the predictions presented here, the effect of dominant articulatory routines should be most evident in early L3 speakers with low L2 proficiency acquiring an L2 allophonic process that they are likely unaware of and that could be transferred from their L1 or their L2 (i.e., they have acquired the L2 process), and whose three languages are all phonologically distant. In this case, a dominant language hypothesis would predict that the L1 process would be transferred. If the L2 were transferred, it would suggest that dominant routines do not play a role. Likewise, the effect of dominant articulatory routines should be smallest in the speech of balanced bilinguals, or highly proficient L2 speakers acquiring L3 phonemes at advanced stages of L3 acquisition, whose three languages share many characteristics. Studying speakers with these characteristics would be the most effective way of investigating factors influencing non-native transfer that are not related to dominant articulatory routines. Future work will need to test to what extent the predictions laid out here are accurate.

The proposal that language dominance plays a role in L3 production does not imply that the dominant language will be the only source of transfer, and the proposal is not a stand-alone model of acquisition. It is simply the recognition that one of the unique aspects of L3PP, which is not shared with the L3 acquisition of morphosyntax/the lexicon, is the physical nature of speech. Similar to other motor skills (e.g., walking, typing, texting, dancing), repetitive patterns become automatized (Namasivayam and Van Lieshout 2011). The less aware speakers are of these patterns, and the greater the need is to rely on automatic routines (e.g., in complex situations, either related to task or motor skill), the more likely dominant movements are to surface (see Namasivayam and Van Lieshout (2011) for discussions comparing motor skill, speech motor skill, and the role of automaticity).

4.4. Limitations and Future Avenues

The results of the present study revealed that task complexity can influence the source of transfer observed, in some but not all cases. One of the key findings was that positive transfer of the L2 flap was more likely in the less complex task, confirming our prediction. However, it is difficult to tease apart facilitative transfer from acquisition, and it raises the question: do the data reflect facilitative transfer, or simply indicate acquisition of the L3 Spanish tap? Positive transfer is not automatic, i.e., the presence of an L3 target segment in the L1 or L2 is not always a sufficient condition for the learner to produce that segment in the L3. On the other hand, if the L3 speaker acquires the target segment, does this automatically reflect transfer, or is it possible to learn an L3 segment with no transfer occurring? While it is not possible to answer this question with 100% certainty, the data do suggest that there was likely some facilitative transfer. If learners were not transferring the L2 English flap, we would not have observed a correlation between the L2 flap and L3 tap accuracy. Another way in which the data can be interpreted is that the learners did not directly transfer an allophone to a phoneme (i.e., the mental representation). It could simply be that speakers who are accustomed to making the articulatory gestures required for the L2 flap tend to more accurately articulate L3 taps, given that they consist of the same articulatory movements. The fact that the correlation disappears with the additional complexity of the sentence task supports this possibility.

Note that some scholars have argued that facilitative transfer is primarily problematic in non-initial state learners. For example, Cabrelli and Pichan (2021, p. 137) state that “it is of note that the participants in each of these studies were tested at later stages of L3 acquisition. Thus, there is a confound since it is not possible to adjudicate between facilitative transfer and L3 acquisition”. Although we would partially agree with this statement, while also highlighting that our correlation provides some support of facilitative transfer, it is important to recognize that facilitative transfer is always somewhat problematic when attempting to identify whether transfer has occurred, regardless of the stage of learning. We know from experimental work that phonological learning can occur in as little as 30 min (Pycha et al. 2003; Moreton 2008; Baer-Henney et al. 2015). Given that initial state L3 production studies (e.g., Cabrelli and Pichan 2021) have used delayed repetition tasks, and that these studies have focused on initial state learners already exposed to several hours of instruction, it is no less problematic to tease apart positive transfer from acquisition in these early learners. Reading tasks are potentially a better option for initial state learners, given that no stimulus is provided, and learners must therefore produce the target with no influencing prompt. Note, however, that orthographic transfer has its own limitations.

Due to the problematic nature of establishing when facilitative transfer occurs, evidence from non-facilitative transfer is most conclusive. Nevertheless, in order to fully comprehend L3 acquisition patterns, it is crucial to understand both facilitative and non-facilitative transfer. The former should thus be considered and included in L3 studies, with the caveat that it does not represent conclusive evidence.

An additional limitation of the present study is that we are assuming that differences in the transfer source due to task complexity reflect the effects of automatic articulatory routines. While this is likely to be the case, we cannot rule out other potential reasons. For example, there could be something about the task that influences the learner to transfer from one language as opposed to another, that is not related to articulatory routines.

5. Conclusions

The goal of the present study was the examine the effect of task type on transfer source, testing the hypothesis that an increase in task complexity will result in less L2 based transfer, due to the fact that learners are expected to rely on more automatic articulatory routines when task complexity increases. The results partially supported the hypothesis—facilitative and non-facilitative transfer were observed for the L2 English flap, whereas non-target L1 /l/ substitutions were also more prevalent. This study therefore provides additional evidence supporting a role for dominant articulatory routines in L3 speech production, while also highlighting the importance of task type in the methodological design and interpretation of the data.