title: Vocal development in infants with Down syndrome and infants who are developing normally.
abstract: The development of early vocalizations was investigated with 13 infants who had Down syndrome and 27 infants who were developing normally at bimonthly intervals from 4 to 18 months of age. A perceptually based framework was used to categorize utterances according to their developmental relations with adult, well-formed, or "canonical" syllables. Over time, both groups demonstrated increased production of mature vowel and canonical consonant-vowel syllables (characterized by full vowels, consonants, and rapid, well-coordinated articulatory movements) and decreased production of less mature "quasi-vowel" and marginal syllables. Infants in both groups were also quite variable in vocal development, both within group and across time.
authors.affiliation: University of Miami, Mailman Center for Child Development, FL 33101.
authors.forename: M L
authors.initials: ML
authors.lastname: Steffens
authors.forename: D K
authors.initials: DK
authors.lastname: Oller
authors.forename: M
authors.initials: M
authors.lastname: Lynch
authors.forename: R C
authors.initials: RC
authors.lastname: Urbano
mesh_terms: D002663:Child Language; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000175:diagnosis*; D004314:Down Syndrome / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006311:Hearing Disorders / Q000209:etiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007804:Language Development; D007806:Language Disorders / Q000175:diagnosis*; D008297:Male; D014705:Verbal Behavior