Articulatory-acoustic vowel space: Associations between acoustic and perceptual measures of clear speech.

PURPOSE: The current investigation examined the relationship between perceptual ratings of speech clarity and acoustic measures of speech production. Included among the acoustic measures was the Articulatory-Acoustic Vowel Space (AAVS), which provides a measure of working formant space derived from continuously sampled formant trajectories in connected speech.

METHOD: Acoustic measures of articulation and listener ratings of speech clarity were obtained from habitual and clear speech samples produced by 10 neurologically healthy adults. Perceptual ratings of speech clarity were obtained from visual-analogue scale ratings and acoustic measures included the AAVS measure, articulation rate and percentage pause.

RESULT: Clear speech was characterised by a higher perceptual clarity rating, slower articulation rate, greater percentage pause and larger AAVS compared to habitual speech. Additionally, correlation analysis revealed a significant relationship between the perceptual clear speech effect and the relative clarity-related change in the AAVS and articulation rate measures.

CONCLUSION: The current findings suggest that, along with speech rate measures, the recently introduced AAVS is sensitive to changes in speech clarity.