Increased language co-activation leads to enhanced cross-linguistic phonetic convergence

Purpose: This study investigates the effects of bilingual language modes (or settings) on the speech production patterns of a group of early Catalan/Spanish bilinguals from Majorca, Spain. Our main research question was as follows: are bilingual speech patterns modulated by the level of (co-)activation of a bilingual’s two languages? Design: Bilingual participants were classified as a function of their linguistic experience (or dominance), from Catalan- to Spanish-dominant. Subsequently, we recorded their speech in two experimental settings: a unilingual setting in which only Catalan words were uttered, and a bilingual setting in which both Catalan and Spanish words (cognates) were produced in random order. Data and analysis: The study examined the acoustic realization of Spanish and Catalan unstressed /a/, which surfaces as [a] in Spanish but is reduced to schwa, [ə], in Catalan. The acoustic characteristics of unstressed /a/ were explored across the two languages and the two experimental settings. Findings: Catalan unstressed /a/, which was similarly reduced to schwa in the speech of all participants, became slightly more similar to Spanish unstressed /a/ (i.e., it had a higher first formant) when produced alongside Spanish words (bilingual setting) than when produced in a Catalan unilingual setting. There were no effects of linguistic experience, and the effects of setting did not interact with experience. Originality: Very few studies have reported the effects of dynamic cross-linguistic interference in phonetic production, and even fewer have reported them with a phonetic variable resulting from a language-specific phonological process (unstressed vowel reduction) rather than a phonemic contrast. Implications: These findings suggest that cross-linguistic interaction is dynamic and modulated by language activation, and that an absence of dominance effects does not necessarily entail an absence of online cross-linguistic phonetic influence.