My Diagonal Life

21st September 2009

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Speech perception by the chinchilla: voiced-voiceless distinction in alveolar plosive consonants

PK Kuhl and JD Miller, 1975

Four chinchillas were trained to distinguish between /t/ and /d/ (the phonetic representations for English, well, t and d.)  The difference between /t/ and /d/ is simply the voice-onset time, or how long after you release the stop (the linguistic term for this type of consonant) before your vocal chords begin to vibrate again as you pronounce the following vowel.  However, there is a whole range of voice-onset times, and humans have a natural threshold above or below which they’ll tend to hear the sound as a particular phoneme (a phoneme is a collection of sounds that are essentially percieved the same by the listener.)  The chinchillas were then played a variety of alveolar stops (/t/ and /d/-like sounds) with varying voice-onset times.  They were found to have very similar thresholds to humans for distinguishing one phoneme from another.

This is evidence for the fact that our linguistic abilities adapted to pre-existing physiological capacities and not the other way around.  Yay chinchillas for contributing to linguistic study!