Discrimination and Identification of Speakers in Native and Non-Native Languages: A Comparison of Monolingual and Bilingual Infants

Abstract

The ability to recognize and track voices is paramount in language development. Voice recognition occurs by discriminating auditory information provided by the speaker. Personal differences create unique voice characteristics and affect the sounds produced in speech, which helps listeners recognize a speaker as uniquely different from others. Discriminating voices is an important process, beginning prenatally and developing in the first stages of language acquisition. This dissertation has as its objective to evaluate bilingual infant's perception of speaker traits and discrimination of voices across and within a native language (i.e., code switching). Study 1 used a sample of 21 bilingual infants (n 7-months=13; n 11-months=8) to explore bilingual ability to track changes in speakers and languages produced. Results showed that bilingual infants at 7- and 11-months track new voices and languages in a native language. Study 2 used a sample of 30 infants (n bilingual=12; n monolingual=18) to explore bilingual ability to track changes in speakers and languages produced within a varied language environment (i.e., one speaker code switching). A monolingual group was added as a point of comparison. Results demonstrated that bilingual infants at 7- and 11-months track speaker identity and notice changes in voices and languages produced in a varied language environment. Bilingual infants at 11-months of age reduced their attention towards language code-switching and maintained focus on changes in speakers. The monolingual infants were able to track changes in speaker and languages despite being tested in a mixture of native and non-native languages. Results from this dissertation highlight the nuances to bilingual and monolingual language development, specifically in the ability of tracking voices. Results add to our understanding of the interconnected development of tracking linguistic and speaker information.