Children's acquisition of speech timing in English: a comparative study of voice onset time and final syllable vowel lengthening.

This study describes English-speaking children's acquisition of voice onset time (VOT), a segmental feature that specifies the timing of word-initial stop consonants, and final-syllable vowel lengthening (FSVL), a suprasegmental feature that influences the timing of vowels. The purpose of this study was to evaluate two hypotheses about the acquisition of speech timing contrasts; a 'motoric' hypothesis predicting that children would control the vowel duration contrast earlier than the consonantal one (FSVL before VOT), and a 'representation' hypothesis predicting that children would control the contrast represented on the segmental level of linguistic description earlier than the contrast represented on the suprasegmental level (VOT before FSVL). Longitudinal acquisition patterns for both contrasts were compared in ten children between the mean ages of 1;6 and 2;0. The results, indicating that English-speaking children usually acquired VOT before FSVL, are discussed in light of evidence that French-speaking children acquire analogous contrasts in the opposite sequence. The crosslanguage comparisons support limited forms of both the motoric and representation hypotheses. As promising topics for further study, the results also suggested the importance of individual differences, and the variability of timing features in the input.