Acquisition and Acoustic Patterns of Southern American English /l/ in Young Children.

Abstract

Purpose The aim of the current study was to examine /l/ developmental patterns in young learners of Southern American English, especially in relation to the effect of word position and phonetic contexts. Method Eighteen children with typically developing speech, aged between 2 and 5 years, produced monosyllabic single words containing singleton /l/ in different word positions (pre- vs. postvocalic /l/) across different vowel contexts (high front vs. low back) and cluster /l/ in different consonant contexts (/pl, bl/ vs. /kl, gl/). Each production was analyzed for its accuracy and acoustic patterns as measured by the first two formant frequencies and their difference (F1, F2, and F2-F1). Results There was great individual variability in /l/ acquisition patterns, with some 2- and 3-year-olds reaching 100% accuracy for prevocalic /l/, while others were below 70%. Overall, accuracy of prevocalic /l/ was higher than that of postvocalic /l/. Acoustic patterns of pre- and postvocalic /l/ showed greater differences in younger children and less apparent differences in 5-year-olds. There were no statistically significant differences between the acoustic patterns of /l/ coded as perceptually acceptable and those coded as misarticulated. There was also no apparent effect of vowel and consonant contexts on /l/ patterns. Conclusion The accuracy patterns of this study suggest an earlier development of /l/, especially prevocalic /l/, than has been reported in previous studies. The differences in acoustic patterns between pre- and postvocalic /l/, which become less apparent with age, may suggest that children alter the way they articulate /l/ with age. No significant acoustic differences between acceptable and misarticulated /l/, especially postvocalic /l/, suggest a gradient nature of /l/ that is dialect specific. This suggests the need for careful consideration of a child's dialect/language background when studying /l/.