Doctoral Dissertation Research: Production and perception of native and non-native speech enhancement

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

In order for speech communication to be successful speakers must be able to deliver their messages clearly to their listeners. For example, when a listener does not understand what was said by a speaker the first time, the speaker may repeat what they said in a clearer manner so that the listener can understand it. This seemingly simple act of enhancing intelligibility of speech for a listener is often carried out naturally by fluent speakers of the language, yet it can be difficult for people who produce less fluent and less intelligible speech, such as non-native speakers of the language. Not being understood by listeners has very real consequences for non-native speakers as it can significantly decrease their opportunities to obtain jobs and education, and more broadly, to participate in society as an equal member. The significance of this issue is highlighted by the growing population of non-native English speakers in the U.S. This project seeks to better understand why it can be difficult to enhance speech intelligibility in a non-native language by examining how speakers of different linguistic backgrounds use speech enhancement strategies in different communication contexts. The results of this project could inform the development of methodologies for second language learning as well as interventions for clinical populations who may experience difficulty enhancing their speech intelligibility. The goal of this project is to understand two aspects of what contributes to enhancing speech intelligibility: what kinds of strategies speakers use to enhance their speech and how these strategies are perceived by listeners. Specifically, the proposed experiments examine how a speaker’s ability to speak clearly is affected by different sources, such as the speaker's language background, characteristics of the speech materials (e.g., familiarity of the words or phrases), and characteristics of the communication context. Further, the project examines how speakers' attempts to enhance speech intelligibility translate to listeners' perception of this speech, including perceived degree of comprehensibility (how easy it is to understand the speech) and perceived degree of speaker effort (how hard the speaker is trying to speak clearly). This project will help us better understand the contributions from both speakers and listeners to enhancing speech intelligibility for a variety of native and non-native speaking 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.