Production of English stressed vowels and interstress intervals within and between words in first and second language acquisition

Abstract

The purpose of this study was to observe the differences between first and second language acquisition in English durational patterns with respect to interstress intervals (ISIs). Production experiments were carried out to investigate the durational patterns used by three groups of speakers: adult native speakers of American English, American third graders, and Japanese learners of English. Two sets of English sentences were devised as the linguistic material, and the sentences in each set differed in the number of nominally unstressed syllables that intervened between a target stressed syllable and the next stressed syllable. These sets of sentences contained two different target stressed vowels, and the ISIs within and between words. The shortest ISIs were produced by adult American speakers regardless of the number of unstressd syllables in the target ISIs. The Japanese learners produced shorter ISIs than the American children in one set of sentences, while in the other set, the American children produced shorter ISIs than the Japanese. Regarding the durations of target stressed vowels, foot-level shortening was observed in the three subject groups, the American children exhibiting the highest percentage of shortening followed by the American adults and then the Japanese.