Dissertations, Theses, and Capstone Projects

Date of Degree

6-2026

Document Type

Doctoral Capstone Project

Degree Name

Doctor of Audiology

Program

Audiology

Advisor

Meital Avivi-Reich

Advisor

Laura Spinu

Subject Categories

Bilingual, Multilingual, and Multicultural Education

Keywords

Speech in Noise, Monolingual Speakers, Bilingual Speakers, Normal Hearing, Working Memory

Abstract

The current study examined how background noise affects the learning of novel phonetic and phonological patterns in speech. While prior research has shown that bilingual participants may learn new phonetic patterns more successfully than monolingual participants under quiet conditions, it remains unclear whether this advantage persists in more ecologically valid listening environments.

We investigated phonetic learning skills in monolingual English speakers (n = 13) and early bilingual speakers (n = 13). Participants were trained and tested on an artificial English accent presented in the presence of 12-talker babble noise (+10 dB SNR). A digit span task was also administered to assess working memory capacity. The accent task included baseline, training, and testing phases and differed from standard North American English in four ways: diphthongization, tapping, epenthesis, and intonation.

Results showed that both groups demonstrated significant learning across phases, with improved performance from baseline to training and testing. However, accuracy decreased as sentence complexity increased. Additionally, no bilingual advantage was observed, contrary to findings from studies conducted in quiet. Instead, group differences varied by feature type, with monolingual participants showing significantly higher accuracy on the MLH intonation feature, consistent with prior evidence that prosodic and segmental learning rely on distinct mechanisms. In the digit span task, monolingual participants showed modestly higher overall accuracy, though this difference was not consistent across all sequence lengths, and both groups showed the expected decline in accuracy as sequence length increased. A significant positive relationship between working memory and accent learning was observed only in bilingual participants, suggesting that cognitive resources may play a more prominent role in learning under challenging listening conditions for this group.

These findings suggest that accent learning is sensitive to listening conditions and that the bilingual advantage may not persist in background noise due to degraded acoustic input. The results highlight the importance of ecological validity in speech-learning research and suggest that perceptual constraints in noise may limit the influence of linguistic experience on learning outcomes. These findings have implications for clinical and educational settings in which bilingual individuals must process and adapt to novel speech patterns under adverse listening conditions.

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