Covert contrast in velar fronting: An acoustic and ultrasound study.
Covert contrast in velar fronting: An acoustic and ultrasound study.
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DOI:
10.3109/02699206.2015.1056884
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发表时间:
2016
影响因子:
1.2
通讯作者:
Mizoguchi A
中科院分区:
文献类型:
--
作者:
McAllister Byun T;Buchwald A;Mizoguchi A
There is growing evidence that speech sound acquisition is a gradual process, with instrumental measures frequently revealing covert contrast in errors perceived to involve phonemic substitution. Ultrasound imaging has the potential to expand our understanding of covert contrast by showing whether a child uses different tongue shapes while producing sounds that are perceived as neutralized. This study used an ultrasound measure (Dorsum Excursion Index) and acoustic measures (VOT and spectral moments of the burst) to investigate overt and covert contrast between velar and alveolar stops in child speech. Participants were two children who produced a perceptually overt velar-alveolar contrast and two children who neutralized the contrast via velar fronting. Both acoustic and ultrasound measures revealed significant differences between perceptually distinct velar and alveolar targets. One child with velar fronting demonstrated covert contrast in one acoustic and one ultrasound measure; the other showed no evidence of contrast. Clinical implications are discussed.