Acoustic and functional characteristics of infants' disyllables and multisyllabic babbling

Pat Blaine Blackwell, Purdue University

Abstract

Disyllables, defined in this study as pairs of canonical-like CV syllables, are related by form to both multisyllabic babbling and children's first words. It is not clear from previous literature when disyllables first appear in an infant's repertoire nor how their appearance relates to that of other similarly structured forms, specifically monosyllables and multisyllabic babbling. The purpose of this study was to identify within the vocalizations of four infants the months of disyllabic emergence and prominence, and to determine how disyllables relate to monosyllables and multisyllables. Emergence was defined as the month in which at least five disyllables were observed within a thirty minute videotaped session. The month of prominence was the month in which the infant produced a greater number of disyllables than multisyllables. Monthly observations started when the infants were six months old. Each session was thirty minutes in length and structured to encourage vocalizations. Disyllables, multisyllables and monosyllables were edited from the videotapes and submitted to spectrographic analysis. Durational measurements were made of (a) syllables, (b) series, that is the form of interest and the vocal context in which it occurred, and (c) the silent intervals between syllables in disyllables and multisyllables. Also observed was the difference in duration of final and non-final syllables. Finally all three forms, disyllables, multisyllables, and monosyllables, were categorized as to whether the form was used by the infant in an interactive manner. The data from all four infants contained a month of disyllabic prominence, a month in which disyllables were more numerous than multisyllables. For all infants the month of emergence was at or near the month of prominence. Disyllables and multisyllables were alike in that their syllables were shorter than those in monosyllables. The silent intervals between syllables, however, tended to be briefer in disyllables. Tendencies toward final syllable lengthening, i.e. slightly elongating the final syllable within a word or utterance, were found in disyllables, but not multisyllables. Disyllables and monosyllables showed more of a tendency to be used in intentional vocalizations than did multisyllables.

Degree

Ph.D.

Advisors

Stark, Purdue University.

Subject Area

Speech therapy|Developmental psychology|Cellular biology

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