The effect of position in utterance on speech segment duration in English.

The duration of speech segments as a function of position in utterances (initial, roedial, final) was studicd. In the first cxpedment seven Engl/sh speakers read nonsense utterances of the form "say a [bab], say a [bgbab], say a [babgb]," etc. Spectragrams were used to determine the duration of speech segments in the readings. Final syllables were found to be longer than nonfinal syllables. F/hal-syllable vowel increments were approxlma•ly 100 msec. F'mal-syllable consonant increments were less than vowel increments; for instance, absolute final consonant increments were about 20 msec. Also word-/nitial consonsnts were found to be lengthened by 20--30 msec over roedial consonants. Subsequent experimentation dcrnonstratcd with English nonsense words that (l) final-syllable and initial-consonant len8thening occur in utterances with various intonational patterns (imperative, dccLarative, interrogative); (2) final-syllable lengthenin 8 occurs in word-fmal and phrase-final poaitions as well as in utterance-tlnal position; and (3) final-syllable and initial-consonant lengthening occur in various kinds of syllables, including syllables with diphthongs, with fricative consonants, with voiceless tops, with consonant cluster, and with no final consonants (i.e., CV syllables). These studies report durational increments of particularly great magnitude for absolute f'mal frieative consonants. Explanations of the lengthening effects are discussed. One theory suggests that lengthening in certain utterance posifiuns iz a learned aspect of language which cues listenera concerning the location of boundaries of words, phrases, or sentences. Explanations based on hypothesized properties of the speech production process are also discussed.