Acquisition of Speech Production: The Achievement of Segmental Independence

As a primate communicative event, the repetitive, rhythmic, open-close alternation of the mandible, accompanied by phonation, is observable in three forms; some variants of the lipsmack, which is widespread in other primates, the initial babbling of human infants, and the production of the syllables of adult speech. In the first two of these, successive cycles tend to be uniform but in the third there is a highly variegated pattern in successive cycles. Adult segmental serial ordering errors, (e.g. spoonerisms) the effects of which are strongly constrained in terms of syllable structure, suggest that variegation is achieved by placement of independently controlled “Content” elements in syllable “Frames”. This paper considers implications of the view that development of infant communicative vocalizations from initial reduplicated babbling to variegated babbling and then to speech, primarily involves a gradual functional differentiation of segmental and subsegmental content elements from a phylogenetically prior basis consisting of ‘pure’ syllable frames; that is, mandibular oscillations without internal articulatory modulation.