Cross-linguistic phonetic interference in spontaneous code-switched speech: an analysis of the SEAME corpus

Abstract Previous research on the phonetic outcomes of code-switching has most commonly found a degree of cross-linguistic interference, although such studies have relied heavily on read-aloud paradigms. Moreover, while prior studies have mostly examined the effect at the point-of-switch, less work has examined potential impacts beyond the point-of-switch. The current study investigates whether the distance from the point-of-switch impacts phonetic outcomes in bilingual vowel production in a Mandarin–English corpus of bilingual speech. English and Mandarin vowels, /æ/ and /e/ respectively, produced by 30 Singaporean speakers were analyzed, along with the distance from the point-of-switch. Results showed evidence of cross-linguistic interference, with English tokens becoming more Mandarin-like, although these effects were modulated by the distance from the point-of-switch. This effect followed a nonlinear trajectory, with the strongest effect at the point-of-switch, indicating a short-term time course of phonetic interference. These results support a transient, decay-oriented cross-linguistic interference model driven by co-activation of both languages and adding to current understandings of language selection and separation mechanisms in bilinguals.