Effect of final-syllable position on vowel duration in infant babbling.

Previous research has suggested possible speech-production- and/or speech-perception-oriented causes for the temporal phenomenon referred to as final-syllable vowel lengthening, yet little conclusive evidence has been adduced for either possibility. The present study represents an attempt to provide additional information concerning the nature of this phenomenon by approaching the issue from a developmental perspective. A much smaller amount of final-syllable vowel lengthening was observed in the premeaningful vocalizations of a number of very young infants than in phonetically comparable utterances produced by adult speakers of English. It is concluded on the basis of this preliminary evidence that extensive final-syllable lengthening observed in the productions of adult speakers of English seemingly constitutes a learned behavior.