Effect of Speech Rate on a Vowel Contrast and Implications for Second Language Training

The present study evaluates talkers’ ability to consciously modify the duration and Euclidean distance of the English high front vowel contrast in a predictable manner by changing their speech rate. Our results concur with previous studies showing that vowel duration is highly sensitive to changes in speech rate, and predictably decreases as speech rate increases. Although some changes in the contrastive distance between the English high front tense and lax vowels were observed, and partly reached statistical significance, a closer look at individual data failed to reveal any reliable pattern, such as a consistent decrease in the vowel distance as speech rate increases. Implications for the design and improvement of second language training programs with difficult non-native contrasts are discussed.