title: Modified spectral tilt affects infants' native-language discrimination of approximants and vowels.
abstract: This study's aim was to determine if 6- and 9-month-old infants discriminate approximants and vowels when the spectral shape is modified to emphasize high- or low-frequency information. Infants were presented with /r/-/l/ and /ɔ/-/ɐ/ in three conditions: (a) unmodified; (b) -6 dB/octave tilt; and (c) +6 dB/octave tilt. Six-month-olds discriminated /ɔ/-/ɐ/ in conditions (a) and (b), and /r/-/l/ in conditions (a) and (c), but 9-month-olds only discriminated when unmodified. The results reflect native-language attunement. Six-month-olds discriminate spectrally modified sounds that emphasize relevant cues, but by 9 months, infants are sensitive to the native spectral profiles of speech.
authors.affiliation: National Acoustic Laboratories, 16 University Avenue, Macquarie University, Sydney, New South Wales, 2109, Australia elizabeth.beach@nal.gov.au.
authors.forename: Elizabeth Francis
authors.initials: EF
authors.lastname: Beach
authors.affiliation: School of Behavioural, Cognitive and Social Science, University of New England, Armidale, New South Wales, 2350, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Noble
authors.affiliation: MARCS Institute for Brain, Behaviour and Development, University of Western Sydney, Penrith, New South Wales, 2750, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Kitamura
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000367:Age Factors; D001302:Audiometry, Speech; D002663:Child Language; D004192:Discrimination, Psychological; D006185:Habituation, Psychophysiologic; D006801:Humans; D007223:Infant; D010700:Phonetics; D010898:Pitch Perception; D013018:Sound Spectrography; D013061:Speech Acoustics; D013997:Time Factors; D014833:Voice Quality