Phonetic shifts in bilingual vowels: Evidence from intersentential and intrasentential code-switching

Aims and objectives: While previous research on code-switching, defined as the alternation between two languages in a single interaction, has focused on syntactic sociopragmatic patterns, significantly less work has focused on the impact of code-switching on phonetics. Distinct types of code-switching have been previously identified, with the distinction between intersentential and intrasentential code-switches being among the most basic. Yet, existing work on the phonetics of code-switching has largely relied on single feature (i.e., voice onset time) and has exclusively examined one type of code-switch (i.e., intrasentential). The current study investigates the potential for cross-linguistic interference in vowel production and examines the potential role of different code-switch types: intersentential and intrasentential code-switching. Design/Methodology: Thirty-seven Korean–English bilinguals participated in a controlled reading paradigm, producing monolingual English, monolingual Korean, intersentential code-switches, and intrasentential code-switches. Data and analysis: Analysis leveraged differences in the Korean and English vowel inventories and focused on the production of English [æ] and the corresponding Korean vowel [e~ε]. Findings/Conclusions: Results indicated that code-switched English vowels shifted in the direction of Korean vowels with respect to both height and backness. Code-switch type was shown to be significant, with a greater degree of vowel shift for intrasentential than intersentential code-switching. Originality: This study adds to the limited prior literature examining the effect of code-switching on vowel quality and is one of the first studies to systematically examine the role of code-switching typology on cross-linguistic interference in the phonetic domain. Significance/Implications: First, this study adds to the limited prior research that specifically examines the effect of code-switching on phonetic production of vowel quality. Second, this study highlights the nuances of short-term cross-linguistic interference, and notably the possibility for differential outcomes of interference across different linguistic domains (e.g., phonetics and syntax), showing a clear role for code-switching typology at the phonetic level.