Tone-evoked Vowels and Semivowels

Prior research has shown that listeners associate pure tones of certain frequencies with certain vowels, with strong associations between high tones and the vowel [i] and between low tones and back rounded vowels [u] and [o]. Studies of this phenomenon with speakers of several languages are reviewed in detail and compared with similar results from experiments involving filtered vowels and sinewave speech. New experiments were conducted in which listeners matched frequencymodulated tones with video of glide-vowel syllables, as glides are a natural dynamic analogue to toneevoked vowels. Results show that the direction, frequency range, and rate of modulation can affect judgments on both parts of the glide-vowel syllable. The labiovelar glide [w] was associated with modulation through the range associated with [u], and the palatal glide [j] with the range associated with [i]. Relative effects of tone frequency are also observed, indicating that in the absence of full spectral cues, the categorical boundaries of toneevoked vowels are flexible and context dependent. Implications for theories of speech perception and for models of spectral recognition are discussed.