Perception of Children's Productions of /l/: Acoustic Correlates and Effects of Listener Experience

Abstract

Introduction: The aim of the current study was to examine the effect of listeners' experience with child speech and phonetic training on perceptual judgment of children's word-initial /l/ productions. The acoustic correlates of acceptable and misarticulated productions of /l/ and their relation to listeners' experience with child speech were explored.

Methods: Three listener groups listened to children's word-initial /l/ productions embedded in monosyllabic words and judged the "/l/-likeness" of the productions using a Visual Analog Scale (VAS). Three listener groups included (a) speech-language pathologists with at least 10 years of experience (SLP group), (b) graduate students in speech-language pathology (GS group), and (c) naïve listeners with no clinical phonetics experience (NL group). Acoustic correlates (both static and dynamic measures) of listeners' perception of /l/ sounds were also investigated.

Results: While mean VAS ratings did not differ significantly by listener group, the SLP group used a wider range of the VAS than the GS and NL groups. Correlational analysis between the static measure (F2-F1 values) and mean listener ratings showed that listeners tend to perceive sounds with the highest F2-F1 values more as /j/ than /l/, while those with the lowest F2-F1 value were perceived more as /w/ than /l/, especially for sounds that are in between phonemic categories. Listener ratings were not highly correlated with dynamic measures.

Conclusion: These results suggest that experienced listeners use the VAS more continuously than less experienced listeners to indicate perception of subphonemic features of children's productions of /l/, and that their ratings correlate with acoustic measures. Furthermore, listeners with experience with child speech and phonetic training are more sensitive to subphonemic features of children's productions of /l/, especially for misarticulated productions. This supports the clinical use of VAS for perceptual judgments of children's /l/ productions.

Keywords: Acoustic measurements; Perceptual rating; Speech; Speech perception.