Language change and linguistic inquiry in a world of multicompetence: Sustained phonetic drift and its implications for behavioral linguistic research

Linguistic studies focusing on monolinguals have often examined individuals with considerable experience using another language. Results of a methodological review suggest that conflating ostensibly ‘multicompetent’ individuals with monolinguals is still common practice. A year-long longitudinal study of speech production demonstrates why this practice is problematic. Adult native English speakers recently arrived in Korea showed significant changes in their production of English stops and vowels (in terms of voice onset time, fundamental frequency, and formant frequencies) during Korean classes and continued to show altered English production a year later, months after their last Korean class. Consistent with an INCIDENTAL PROCESSING HYPOTHESIS (IPH) concerning the processing of ambient linguistic input, some changes persisted even in speakers who reported limited active use of Korean in their daily life. These patterns thus suggest that the linguistic experience obtained in a foreign language environment induces and then prolongs restructuring of the native language, making the multicompetent native speaker in a foreign language environment unrepresentative of a monolingual in a native language environment. Such restructuring supports the view that one’s native language continues to evolve in adulthood, highlighting the need for researchers to be explicit about a population under study and to accordingly control (and describe) language background in a study sample