Cross-language study of speech-pattern learning

In order to investigate the nature of some processes in speech acquisition, synthetic speechlike stimuli were played to groups of English and French children between two and fourteen years of age. The acoustic parameters varied were voice onset time and first-formant transition. Three stages were observed in the development of children’s labeling behavior. These were called scattered labeling, progressive labeling, and categorical labeling, respectively. Individual response patterns were examined. The first stage (scattered labeling) includes mostly children of two to three years of age for the English and up to about four for the French. Children label most confidently those stimuli closest in physical terms to those of their natural speech environment. All stimuli with intermediate VOT values are labeled quasirandomly. Progressive labeling behavior is found mostly amongst children aged three and four for the English, up to about seven for the French. Children’s response curves go progressively—almost linearly—from one type of label (voiced) to the other (voiceless): response follows stimulus continuum. Categorical labeling becomes the dominant pattern only at the age of five to six for the English, one or two years later for the French. This development was found to be highly significant (p smaller than 0.003 for both English and French, using Kendall’s tau measure of correlation). English children learn to make use of the F1 transition feature around five years, whereas French children never use it as a voicing cue. French children will have fewer features than English children at their disposal: This may account for the later age at which French children, as a group, reach the various labeling behavior stages, and for labeling curves being less sharply categorical for French than for English children. These findings indicate that categorical labeling for speech sounds is not innate but learned through a relatively slow process which is to a certain extent language specific. The implications of the results are discussed in the light of previous work in the field.