In this paper we address the question of whether it is possible to compare two theoretical approaches to the same phenomenon or whether these should be considered incommensurable. We focus on two contrasting approaches to the identification of code-switching vs.
borrowing by Poplack and Meechan [1
] and Myers-Scotton [2
]. For Poplack the distinction is based on linguistic integration and for Myers-Scotton on frequency. We show how what is a definition for one is a hypothesis for the other, and vice versa
. Overcoming this apparent incommensurability requires a theory-independent approach in which we define the unit of analysis as “donor-language items” rather than switches or borrowings. Using this unit of analysis in the analysis of English-origin verbs in a Welsh corpus, we examine the assumptions behind the contrasting definitions of CS vs.
borrowing. First we consider whether it is possible to identify linguistic integration in an unequivocal, categorical way and secondly whether linguistic integration is related to frequency of usage. We show that the identification of linguistic integration depends on the test used and that both frequency of usage and listedness play roles in the integration of English donor-language items in Welsh. In this way we argue that we achieve a theory-independent approach and go some way towards overcoming incommensurability.