Early apical stop production: A voice onset time analysis

Abstract

Voice onset time (VOT) has been shown to differentiate effectively the phonemic categories of stop consonants along the voicing dimension. This study involved the measurement of VOT from spectrograms of apical stops produced by young children acquiring American English. Stops were measured from three children recorded regularly between 1 and 2 years of age and from additional children ranging in age from 6 months to 4½ years. Frequency distributions of apical stops along the VOT continuum are compared longitudinally across subjects and with distributions of adult productions of word-initial /d/ and /t/. Drawing on a physiological discussion of the control of timing between stop release and onset of vocal fold oscillation, a pattern of apical stop development is proposed. The earliest examples of stops, around 6 months of age, have uniform distributions along the VOT continuum. Later the distributions of apical stops collapse into an interval corresponding to that of American English /d/. With further development some apical stops are added in the range of adult /t/. The distributions for both /d/ and /t/ words are similar between the ages of 2 and 4½ years, but they do not yet correspond to those of adults.