Dynamics of phonetic-level language control in language switching with a letter-naming paradigm

Aims:<br/>How bilinguals control multiple languages is the object of intense recent scientific debate. Empirical research on language control at various linguistic levels has remained scarce, with language control at the phonetic level particularly underexplored. The present study aimed to examine the dynamics of phonetic-level language control during speech production.<br/><br/>Design:<br/>Chinese-English-German speakers named the letter of the alphabet in English (L2) or German (L3), either in single-language blocks or in alternate-language mixed blocks. Letters vary regarding how phonetically similar pronunciation is across the two languages, hence allowing to explore cross-language phonetic influences.<br/><br/>Data and analysis:<br/>Three-way repeated-measures analysis of variance (ANOVA) with trial type (non-switch vs. single-language for mixing costs; non-switch vs. switch for switch costs), response language (English/L2 vs. German/L3), and phonetic similarity (similar vs. neutral vs. different) as variables were conducted on 52 subjects’ response times and accuracy for mixing costs and switch costs, respectively.<br/><br/>Findings:<br/>Results showed substantial mixing and switch costs, as well as a “reversed language dominance” effect, suggesting inhibitory control in response to cross-language phonetic interference. Cross-language facilitation was observed for phonetically similar letters, and mixing/switch costs were modulated by phonetic similarity in a complex pattern.<br/><br/>Originality:<br/>The findings show a complex interplay of suppression (e.g., as indexed by switch costs) and facilitation (i.e., the effect of phonetic similarity between letter translation equivalents).<br/><br/>Significance:<br/>The evidence for cross-language phonetic interference as well as facilitation effects at local and global levels of control implies a dynamic interaction between the two phonetic systems.