Lab Projects

Speech perception in bilinguals

When people listen to speech, their ability to hear the difference between certain speech sounds is affected by their native language. For example, native speakers of Korean typically have a very hard time hearing the difference between the R and L sounds in English. Likewise, native English speakers typically have a very hard time hearing the difference between the plain, aspirated, and tense stop consonants (e.g. [p], [ph], [p']) of Korean. However, the majority of research on speech perception has focused on people who speak only one language. What if you are a proficient speaker of multiple languages? Current studies in the lab are exploring this question, asking whether bilingual listeners are similar to or different from monolinguals in how they hear speech sounds. For example, does a Korean-English bilingual discriminate English R/L just as easily as an English monolingual, and discriminate Korean stop consonants just as easily as a Korean monolingual? If not, is a bilingual person's perception of speech sounds determined primarily by what age they were when they learned a language, or by how predominantly they use the language?

The role of input statistics in phonetic processing

Previous research has documented a phenomenon known as ‘categorical perception’, in which two sounds corresponding to a single phonetic category are poorly discriminated by listeners, while two sounds corresponding to different phonetic categories are discriminated well (Liberman et al., 1957). Since each language employs a unique set of phonetic categories, this results in different patterns of discrimination for speakers of different languages (Abramson & Lisker, 1970). Our research has found that the effect of the native language on the perception of speech sounds is not static; rather, adult listeners are acutely sensitive to the statistical properties of their phonetic environment. As these properties of the input change, so does listeners’ pattern of speech sound discrimination and word identification. Current experiments are investigating the manner by which this phonetic learning occurs, and the factors that may constrain such learning.