Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Arts (BA)
Previous research has shown that speakers of English use vowel length as a subphonemic cue to the voicing of a following obstruent. Countless studies have demonstrated adults’ ability to make a voicing judgement based upon vowel length but studies with children have provided mixed and sometimes conflicting results. In the present study, we sought to first determine whether adults would exhibit varying sensitivity to vowel length based upon whether it is found in a position where it is predictive of the phonemic status of another sound (i.e. serving as a subphonemic cue). Second, we removed top-down information in order to isolate the acoustic system and better understand children’s sensitivity to subphonemic vowel length from 4 to 6 years of age. Both adults and children completed a sound discrimination task where they listened to pairs of nonce words that differed only in the length of their vowel and were asked to indicate their level of similarity. In the adult study (N=63), participants revealed higher levels of sensitivity to vowel length preceding an obstruent showing that a subphonemic position boosts perceptibility for vowel length. Results from the child studies (N=73, MEAN AGE=5;5.6) demonstrate that children from 4 to 6 years of age treat subphonemic vowel length quite differently from adults. First, children fail to show sensitivity at the same level as adults. Specifically, 5- and 6-year-olds require vowel length differences that are twice as large to show sensitivity and 4-year-olds do not show sensitivity even at the larger lengths. Second, children do not reveal varying sensitivity based upon whether the vowel is in a location where it could be used subphonemically. Together, this study reveals that children from 4 to 6 months of age are unable to demonstrate subphonemic sensitivity at least when tested in an explicit way similar to adults. This suggests that children have not fully developed their native phonology by the time they are 6-years-old.
Fergus, Abby, "Accessing the Gray Area Between Phonetics and Phonology: the Development of Vowel Length as a Subphonemic Cue" (2021). Undergraduate Honors Theses. William & Mary. Paper 1719.