Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

Susan Nittrouer

Second Advisor

Walt Jesteadt

Third Advisor

John Christensen


Previous studies have found that children’s judgments of syllable-initial /s/ and / ∫ / are more related to the vocalic F2 transition and less related to the fricative-noise spectrum than are adults’ judgments [Nittrouer & Studdert- Kennedy, JSHR, 30 (1987); Nittrouer, J. Phon., 20 1992]. These results have been taken as evidence that young children organize linguistic input in units more closely approximating syllable size than phoneme size. Furthermore, such results have led to a model of speech development proposing that children’s weighting of the acoustic cues for phonemic categories changes as they gain linguistic experience, with a general shift in weighting away from dynamic acoustic parameters (those associated with overall syllable production) towards more static acoustic parameters (those associated with the individual phonemic segments of which the syllable is composed). The present study investigated identification by adults and by 3 & 1/2-year-olds of syllable-initial fricatives for stimuli with either natural or synthetic vocalic portions. The two goals of this work were (1) to see if previous findings indicating children’s enhanced weighting of formant transitions and diminished weighting of fricative-noise spectra could be replicated for stimuli with natural vocalic portions, and (2) to see if these same patterns would be demonstrated for stimuli with synthetic vocalic portions. Results for children showed that the previously observed patterns of weighting of speech-relevant acoustic information held for stimuli with natural vocalic portions only. For stimuli with synthetic vocalic portions, children’s results resembled those of adults. That is, their judgments of fricative identity were more strongly related to the fricative-noise spectrum and less strongly related to the vocalic F2 transition than those judgments had been for stimuli with natural vocalic portions. It was concluded that children’s weighting schemes are not simply the consequence of immature psychoacoustic capacities, and that certain schemes are specific to speech stimuli.


Thesis Presented to the Department of Special Education and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Arts University of Nebraska at Omaha.

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