Accent evaluation from extemporaneous child speech

Abstract

A key issue in judging foreign accent is to isolate the phonetic component from potentially confounding higher-level factors such as grammatical or prosodic errors which arise when using natural sentence-length speech material. The current study evaluated accent and intelligibility ratings of children’s speech for isolated words spliced out of extemporaneous material elicited via a picture description task. Experiment 1 demonstrated that word scores and accent ratings provided by native judges pattern as in earlier studies, validating the use of word-based material derived from natural speech. In a second experiment, listeners rated the degree of foreign accent and comprehensibility for unrelated sequences of 1 to 8 words from the same talker. Degree of foreign accent was judged to increase with sequence length, asymptoting by 2 word sequences, although listeners did not rate the sequence based on the most-accented word it contains. Comprehensibility was judged to be lower as sequence length increased, asymptoting at 4 words. These findings suggest that short sequences of randomly-permuted words extracted from extemporaneous speech can be used for robust accent and comprehensibility judgements whose focus is on the phonetic basis for deviations from the native norm.