Search Results (21)

A brain–computer interface (BCI) enables direct communication between the brain and external devices by translating neural activity into executable control commands. Among electroencephalography (EEG)-based paradigms, steady-state visual evoked potential (SSVEP) is widely adopted due to its high signal-to-noise ratio, robustness, and minimal calibration requirements. While SSVEP-based spellers have been extensively investigated, many existing systems rely on high-channel-density EEG recordings and computationally complex processing pipelines, and are primarily designed for alphabetic input structures. In this study, we present an SSVEP-based Korean speller that integrates the Cheonjiin keyboard layout to support intuitive composition of Hangul syllables. The proposed system adopts a simple configuration, employing only five visual stimulation frequencies (6.67–12 Hz) and two occipital EEG channels (O1 and O2), with real-time frequency recognition performed using canonical correlation analysis (CCA) within a 1.5 s sliding window. EEG signals were acquired at 200 Hz using an OpenBCI Ganglion board, band-pass filtered (5–45 Hz), and processed with harmonic sinusoidal reference templates for multi-frequency classification. The proposed interface generates five control commands (up, down, left, right, and select), enabling directional cursor navigation and character confirmation on a 4 × 4 virtual Cheonjiin keyboard. Experimental validation with three healthy participants demonstrated an average classification accuracy of approximately 82% and an information transfer rate (ITR) of 31.2 bits/min. Frequency-domain analysis revealed clear spectral peaks at the stimulation frequencies and their harmonics, indicating reliable SSVEP responses. The proposed system employs a simple two-channel configuration integrated with a Korean language-specific input structure, demonstrating that reliable SSVEP-based communication can be realized without computationally intensive algorithms or high-cost EEG acquisition systems. These findings demonstrate that reliable SSVEP-based communication can be achieved using a low-channel configuration without reliance on high-cost EEG equipment. Full article

The Converter/Distributor (C/D) model, as proposed by Fujimura is theoretically grounded on articulatory observations of X-ray microbeam (XRMB) data that show that utterance syllable prominence patterns “dictate” the size, timing and phrasing of articulatory movements. This paper briefly addresses some key differences between the C/D model and Articulatory Prosody (AP) before moving on to describe some of the basic components of the C/D model, e.g., the phonological prosodic input to the model, the Converter, which outputs, among other things, descriptions of syllable prominence patterns, prosodic boundaries, and syllable edge features, and the Distributor which enlists “elemental gestures” to articulatorily implement feature sets. Examples from previous research inspired by the C/D model illustrate how articulatory events, i.e., patterns of jaw lowering, account for the temporal organization of spoken language; also, how second language speakers tend to carry over their first language patterns of jaw lowering. Some applications of the C/D model are discussed, including first and second language acquisition, clinical applications, and new insights into prosodic phonology. The final section summarizes some of the strengths of the C/D model as well as the yet-to-be investigated aspects of the model. Full article

Phonemic processing is largely influenced by how stimulus-specific characteristics of a language are computed, but person-level variables represent important moderators as well. The current study investigates how such characteristics, in parallel, affect receptive-level phonemic processing across the preschool age, and whether these effects are comparable across different languages. Using a child-friendly ‘odd-man-out’ discrimination task, we examined 239 monolingual German- and French-speaking preschoolers, aged three to five. Results revealed that phonotactic probability-based syllable frequency, nonword length, and mismatching nonword positioning effects explained independent variance components of phonemic processing. Age significantly affected how memory-related, but not linguistically relevant, stimulus characteristics were utilized for phonemic processing. Additionally, cross-language differences in rhythmic structure between German and French influenced which nonword segments received more attention focus. These findings provide novel insights into critical determinants of phonemic processing in preschoolers and highlight the need for further research to explore these effects over time and within varying language backgrounds. Full article

Syllable stress can help to quickly identify words in a language with variable stress placement like German. Here, we asked at what age incorrect syllable stress impairs language learners’ attempts to assign meaning to familiar words. We recorded the looking times of young children learning German aged from 4 to 15 months (infants, N69) and 2 to 4 years (toddlers, N28). Participants saw displays of two pictures (e.g., a car and a baby); one of both objects (the target) was named. The disyllabic name of the target was either correctly stressed on the first syllable (“BA.by”) or it was incorrectly stressed on the second syllable (“ba.BY”). On average, all children looked more at the target when they heard its correctly stressed name (compared to the incorrectly stressed name). Furthermore, the analyses of growth curves for all children showed a steeper increase in looking time at the target picture when children heard the correctly stressed target’s name compared to the incorrectly stressed name. These results thus suggest that even very young German-learning children use syllable stress for incremental word-meaning mapping. However, separate post hoc analyses revealed robust differences in overall target fixations only in toddlers but not in infants. The stronger effects in toddlers compared to infants could be related either to the growing vocabulary or the increasing sensitivity to word stress with increasing age. Full article

Background: Understanding the origin and natural organization of early infant vocalizations is important for predicting communication and language abilities in later years. The very frequent production of speech-like vocalizations (hereafter “protophones”), occurring largely independently of interaction, is part of this developmental process. Objectives: This study aims to investigate the gap durations (time intervals) between protophones, comparing typically developing (TD) infants and infants later diagnosed with autism spectrum disorder (ASD) in a naturalistic setting where endogenous protophones occur frequently. Additionally, we explore potential age-related variations and sex differences in gap durations. Methods: We analyzed ~1500 five min recording segments from longitudinal all-day home recordings of 147 infants (103 TD infants and 44 autistic infants) during their first year of life. The data included over 90,000 infant protophones. Human coding was employed to ensure maximally accurate timing data. This method included the human judgment of gap durations specified based on time-domain and spectrographic displays. Results and Conclusions: Short gap durations occurred between protophones produced by infants, with a mode between 301 and 400 ms, roughly the length of an infant syllable, across all diagnoses, sex, and age groups. However, we found significant differences in the gap duration distributions between ASD and TD groups when infant-directed speech (IDS) was relatively frequent, as well as across age groups and sexes. The Generalized Linear Modeling (GLM) results confirmed these findings and revealed longer gap durations associated with higher IDS, female sex, older age, and TD diagnosis. Age-related differences and sex differences were highly significant for both diagnosis groups. Full article

Effective language processing relies on pattern detection. Spanish monolinguals predict verb tense through stress–suffix associations: a stressed first syllable signals present tense, while an unstressed first syllable signals past tense. Low-proficiency second language (L2) Spanish learners struggle to detect these associations, and we investigated whether they benefit from game-based training. We examined the effects of four variables on their ability to detect stress–suffix associations: three linguistic variables—verbs’ lexical stress (oxytones/paroxytones), first-syllable structure (consonant–vowel, CV/consonant–vowel–consonant, CVC), and phonotactic probability—and one learner variable—working memory (WM) span. Beginner English learners of Spanish played a digital game focused on stress–suffix associations for 10 days and completed a Spanish proficiency test (Lextale-Esp), a Spanish background and use questionnaire, and a Corsi WM task. The results revealed moderate gains in the acquisition of stress–suffix associations. Accuracy gains were observed for CV verbs and oxytones, and overall reaction times (RTs) decreased with gameplay. Higher-WM learners were more accurate and slower than lower-WM learners in all verb-type conditions. Our findings suggest that prosody influences word activation and that digital gaming can help learners attend to L2 inflectional morphology. Full article

The aim of this study was to test the Implicit Prosody Hypothesis using a reading corpus, i.e., a text without experimental manipulation labelled with eye-tracking parameters. For this purpose, a bilingual Croatian–English reading corpus was analysed. In prosodic terms, Croatian and English are at the opposite ends of the spectrum: English is considered a time-framed language, while Croatian is a syllable-framed language. This difference served as a kind of experimental control in this study on natural reading. The results show that readers’ eyes lingered more on stressed syllables than on the arrangement of stressed and unstressed syllables for both languages. This is especially pronounced for English, a language with greater differences in the duration of stressed and unstressed syllables. This study provides indirect evidence in favour of the Implicit Prosody Hypothesis, i.e., the idea that readers are guided by their inner voice with its suprasegmental features when reading silently. The differences between the languages can be traced back to the typological differences in stress in English and Croatian. Full article

Background/Objectives: The Implicit Prosody Hypothesis (IPH) posits that individuals generate internal prosodic representations during silent reading, mirroring those produced in spoken language. While converging behavioral evidence supports the IPH, the underlying neurocognitive mechanisms remain largely unknown. Therefore, this study investigated the neurophysiological markers of sensitivity to speech rhythm cues during silent word reading. Methods: EEGs were recorded while participants silently read four-word sequences, each composed of either trochaic words (stressed on the first syllable) or iambic words (stressed on the second syllable). Each sequence was followed by a target word that was either metrically congruent or incongruent with the preceding rhythmic pattern. To investigate the effects of metrical expectancy and lexical stress type, we examined single-trial event-related potentials (ERPs) and time–frequency representations (TFRs) time-locked to target words. Results: The results showed significant differences based on the stress pattern expectancy and type. Specifically, words that carried unexpected stress elicited larger ERP negativities between 240 and 628 ms after the word onset. Furthermore, different frequency bands were sensitive to distinct aspects of the rhythmic structure in language. Alpha activity tracked the rhythmic expectations, and theta and beta activities were sensitive to both the expected rhythms and specific locations of the stressed syllables. Conclusions: The findings clarify neurocognitive mechanisms of phonological and lexical mental representations during silent reading using a conservative data-driven approach. Similarity with neural response patterns previously reported for spoken language contexts suggests shared neural networks for implicit and explicit speech rhythm processing, further supporting the IPH and emphasizing the centrality of prosody in reading. Full article

This study explores the extent to which Palenquero/Spanish bilinguals, a population that is said to have a residual high tone of African origin, keep their two languages temporally and intonationally distinct across statements. While creole languages that emerged from the contact of African and European languages, such as Palenquero, may develop hybrid prosodic systems with tones from substrate languages, and stress from the majority language, language-specific prosody might be expected to converge or simplify over the course of time. As prosodic convergence seems to be inescapable under Palenquero’s circumstances, which factors could support language-specific prosody in this population, if there are any? Two-hundred and thirty-four five-syllable statements were elicited through a discourse completion task, with the participation of ten Palenquero/Spanish bilinguals, in two unilingual sessions. Both phrase-final lengthening and F0 contours were assessed using linear mixed-effects models testing their association with final stress, language, and generation. F0 contours were dimensionally reduced using functional principal component analysis. Despite the strong similarities between the two languages, results indicate that both groups keep their two languages intonationally distinct using plateau-shaped contours in Palenquero initial rises followed by steeper declinations in Spanish. However, elderly bilinguals implement penultimate lengthening language-specifically, being more pronounced in Palenquero. Adults, in contrast, do not show this distinction. In addition to this, elderly speakers show hyperarticulation in Spanish intonation, increasing the difference between their languages. This leads us to believe that adults exhibit a more simplified prosodic system between their languages, relative to elderly bilinguals. In spite of such differences, both generations seem to have the same underlying process (perhaps a substrate effect) driving plateau-shaped intonation in Palenquero, which enhances language differentiation. Full article

This paper discusses the challenges posed in creating a Computer-Assisted Pronunciation Training (CAPT) environment for multiple languages. By selecting one language from each of three different language families, we show that a single environment may be tailored to cater for different target languages. We detail the challenges faced during the development of a multimodal CAPT environment comprising a toolkit that manages mobile applications using speech signal processing, visualization, and estimation algorithms. Since the applied underlying mathematical and phonological models, as well as the feedback production algorithms, are based on sound signal processing and modeling rather than on particular languages, the system is language-agnostic and serves as an open toolkit for developing phrasal intonation training exercises for an open selection of languages. However, it was necessary to tailor the CAPT environment to the language-specific particularities in the multilingual setups, especially the additional requirements for adequate and consistent speech evaluation and feedback production. In our work, we describe our response to the challenges in visualizing and segmenting recorded pitch signals and modeling the language melody and rhythm necessary for such a multilingual adaptation, particularly for tonal syllable-timed and mora-timed languages. Full article

Ideophones are believed to exhibit distinct phonotactic patterns compared to regular language, in their expressiveness. Vowel harmony can be observed in ideophones in Modern Korean. However, over time, Korean has gradually lost its regular vowel harmony process, due to the influx of foreign words, especially from Chinese, and historical sound changes like the vowel shift of /ɔ/ to different vowel types. Previous studies have mainly focused on the vowel patterns of ideophones without necessarily comparing the degree of vowel harmony between ideophones and other lexical strata. This lack of comparison makes it challenging to assess the level of corruption in vowel harmony specifically within ideophones, relative to other components of the lexicon. To address this gap, this paper examines vowel patterns extracted from the online dictionary of Korean, developed by the National Institute of the Korean Language (NIKL) with contributions from anonymous users and specialists. The analysis specifically explores vowel patterns across lexical items with varying syllable lengths, focusing on the lexical stratum, adverbial parts of speech, and the semantic meaning of the adverbials. This examination aims to assess the regularity of vowel sequencing and determine the extent of purity in vowel harmony patterns. The quantitative analysis of the compiled dictionary provides valuable insights into the degree of irregular phonotactics and its relationship to sound symbolism in Modern Korean. Full article

How speech prosody is processed in the brain during language production remains an unsolved issue. The present work used the phrase-recall paradigm to analyze brain oscillation underpinning rhythmic processing in speech production. Participants were told to recall target speeches aloud consisting of verb–noun pairings with a common (e.g., [2+2], the numbers in brackets represent the number of syllables) or uncommon (e.g., [1+3]) rhythmic pattern. Target speeches were preceded by rhythmic musical patterns, either congruent or incongruent, created by using pure tones at various temporal intervals. Electroencephalogram signals were recorded throughout the experiment. Behavioral results in 2+2 target speeches showed a rhythmic priming effect when comparing congruent and incongruent conditions. Cerebral-acoustic coherence analysis showed that neural activities synchronized with the rhythmic patterns of primes. Furthermore, target phrases that had congruent rhythmic patterns with a prime rhythm were associated with increased theta-band (4–8 Hz) activity in the time window of 400–800 ms in both the 2+2 and 1+3 target conditions. These findings suggest that rhythmic patterns can be processed online. Neural activities synchronize with the rhythmic input and speakers create an abstract rhythmic pattern before and during articulation in speech production. Full article

The ability to accurately repeat meaningless nonwords or lists of spoken digits in correct order have been associated with vocabulary acquisition in both first and second language. Individual differences in these tasks are thought to depend on the phonological loop component of working memory. However, phonological working memory may itself depend on more elementary processes. We asked whether auditory non-verbal short-term memory (STM) for patterns in time supports immediate recall of speech-based sequences. Participants tapped temporal sequences consisting of short and long beeps and repeated nonsense sentences sounding like their native language or an unfamiliar language. As a language learning task, they also memorized familiar-word–foreign-word pairs. Word learning was directly predicted by nonsense sentence repetition accuracy. It was also predicted by temporal pattern STM. However, this association was mediated by performance on the repetition measure. We propose that STM for temporal patterns may reflect a component skill that provides the context signal necessary to encode order in phonological STM. It would be needed to support representation of the prosodic profile of language material, which allows syllables in words and words in sentences to be ordered and temporally grouped for short-term representation and long-term learning. Full article

Developmental dyslexia is typically defined as a difficulty with an individual’s command of written language, arising from deficits in phonological awareness. However, motor entrainment difficulties in non-linguistic synchronization and time-keeping tasks have also been reported. Such findings gave rise to proposals of an underlying rhythm processing deficit in dyslexia, even though to date, evidence for impaired motor entrainment with the rhythm of natural speech is rather scarce, and the role of speech rhythm in phonological awareness is unclear. The present study aimed to fill these gaps. Dyslexic adults and age-matched control participants with variable levels of previous music training completed a series of experimental tasks assessing phoneme processing, rhythm perception, and motor entrainment abilities. In a rhythm entrainment task, participants tapped along to the perceived beat of natural spoken sentences. In a phoneme processing task, participants monitored for sonorant and obstruent phonemes embedded in nonsense strings. Individual sensorimotor skills were assessed using a number of screening tests. The results lacked evidence for a motor impairment or a general motor entrainment difficulty in dyslexia, at least among adult participants of the study. Instead, the results showed that the participants’ performance in the phonemic task was predictive of their performance in the rhythmic task, but not vice versa, suggesting that atypical rhythm processing in dyslexia may be the consequence, but not the cause, of dyslexic difficulties with phoneme-level encoding. No evidence for a deficit in the entrainment to the syllable rate in dyslexic adults was found. Rather, metrically weak syllables were significantly less often at the center of rhythmic attention in dyslexic adults as compared to neurotypical controls, with an increased tendency in musically trained participants. This finding could not be explained by an auditory deficit in the processing of acoustic-prosodic cues to the rhythm structure, but it is likely to be related to the well-documented auditory short-term memory issue in dyslexia. Full article

For the last decades neuroscientists have grown interest in the analysis of the rhythmic activity of the brain syn- chronized at temporal and spatial level. These neural oscillations, grouped by their frequency, have been pro- posed to govern all cognitive processes. In the field of the neurobiology of language, considerable research has linked speech processing and language comprehension to neural oscillations. On one hand, neural rhythmic ac- tivity is thought to synchronize to relevant spectral information of speech on three-time scales – which physically reflect phoneme, syllable and phrase processing. On the other hand, syntactic and semantic processing is sub- served by faster oscillatory patterns not necessarily related to the acoustic properties of speech. For each linguistic process, this article summarizes the neural oscillations involved. Further evidence comes from studies on language-related pathologies. Full article