Summary: | Previous research has revealed that very young infants discriminate most speech
contrasts with which they are presented whether the contrasts are native or non-native while
adults have difficulty discriminating non-native speech contrasts but easily discriminate
those contrasts holding meaningful (phonemic) status in their native language. Several
studies have shown that this reorganization in phonetic perception from language-general
perception to language-specific perception occurs at about 10 to 12 months: infants this age
attend only to native phonemic contrasts. It is of interest to determine if exposure to a
phonetic variant plays an important role in influencing perception. We know from previous
research that absence of exposure does not always lead to a lack of discrimination. This
thesis was designed to determine if exposure per se maintains discriminability. To this end
English-speaking adults and infants were tested using a phonetic distinction that does not
hold phonemic status in English but does occur in English. This distinction involves the
phonetic variants [da] and the stop produced following /s/ transcribed as [ta].
When tested in an identification procedure, English-speaking adults identify both
[da] and (s)[ta] as members of one English phonemic category (i.e. [da]). When tested in a
discrimination procedure and a category change procedure, adults discriminate (s) [ta] from
[da] (albeit not as well as would be expected for a native phonemic contrast). With respect
to infants, 6- to 8-month-olds discriminate this distinction revealing further support for
broad-based phonetic perception at this age. However, 10- to 12-month-old infants do not
discriminate, suggesting that the native phonemic status of the contrast (but not exposure)
is the important factor in the reorganization. Discussion centers around how these results
add to the existing literature and why infants of 10- to 12-months would fail to discriminate
a native phonetic distinction. === Arts, Faculty of === Psychology, Department of === Graduate
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