Acoustic variability and speaker discriminative power of liquids in American English.

Abstract

In American English, liquid sounds /r/ and /l/ are the most articulatorily variable and complex sounds. In previous work [Zhou et al., J. Acoust. Soc. Am. 123, pp. 4466–4481 (2008)], we found that the acoustic variability of /r/ due to two different tongue shapes (“retroflex” versus “bunched”) is reflected at the fourth and fifth formants. In order to understand how this articulatory diversity contributes to the intra‐ and interspeaker variabilities in speech signals of liquid sounds, an analysis of variance (ANOVA) analysis has been performed to investigate the intra‐ and interspeaker variabilities of liquid sounds across different frequency subbands. The Buckeye database was analyzed in this study, which includes about 30–60 min of broadband conversation speech for each of 40 speakers. The ANOVA analysis showed that liquids have the maximum F‐ratios (interspeaker variance/intraspeaker variance) in the range of about 3–5 kHz, and /l/ has a larger maximum F‐ratio than /r/. In general, liquids have larger F‐ratios than stops and fricatives and have smaller F‐ratios than vowels and nasals. The results of phoneme‐based speaker identification task will be presented to show the speaker discriminative power of liquids along with the results for other phonemes such as vowels and nasals.