Doctoral Dissertation Research: An examination of language change and dialect change in tandem

Human beings constantly change the way they speak. Discovering how and why people change their speech is key to understanding knowledge of language. Previous research has shown that people quickly change their way of speaking when they talk to one another, in a phenomenon known as phonetic accommodation.

People may also quickly change the way they speak and listen to their first language (L1) when they learn a second language (L2), in a process called phonetic drift. While these two processes of speech change may be connected, they have not yet been studied in tandem. This doctoral dissertation project investigates both how bilingual speakers adjust their L2 when exposed to a person who speaks a different variety of the L2, and how this experience affects the bilingual speaker’s L1.

Because previous research has largely focused on native speakers or on nonnative speakers who learned their L2 later in life, this project instead examines nonnative speakers who learned their L2 early in life – early bilinguals. Early bilinguals are of scientific interest because they show similarities to native speakers but also to nonnative speakers.

This project gathers experimental data on speech production and perception in early bilinguals during interactions with another speaker. The findings contribute to a scientific understanding of how sound changes occur in bilingual individuals and have implications for research on the bilingual brain. This project also benefits society by providing educational opportunities and workforce development skills for students.

Bilingual people who learn a second language (L2) early and use it regularly in daily life raise key questions about what shapes bilingual speech. Some early bilingual speakers, despite their similarities to native speakers, show differences in how their first language (L1) influences their L2. This doctoral dissertation project tests theories of L2 production and perception by examining within-speaker language and dialect change across two bilingual populations, each with a distinct L1 background, living in different language environments.

The project advances three aims: (1) to analyze how bilingual speakers modify their L2 speech production when exposed to a foreign variety of that language (i.e., L2 phonetic accommodation), (2) to identify short-term changes in L1 speech production following L2 phonetic accommodation (i.e., L1 production drift), and (3) to investigate short-term changes in L1 speech perception following L2 phonetic accommodation (i.e., L1 perceptual drift) along with the relationship between perception and production changes. By comparing groups with different L1 backgrounds and language environments, the project provides insight into the roles of linguistic background and ambient language context in L2 phonetic accommodation and L1 phonetic drift.

Participants are early bilingual speakers in two distinct environments. Demographic data comes from a background questionnaire, and acoustic and perceptual data from a series of production and perception tasks (e.g., picture naming, shadowing, forced-choice identification). The results contribute to a broader understanding of bilingual phonetics, the dynamics of cross-linguistic influence, and the factors shaping language change in bilingual populations.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.