Pitch range variation in English tonal contrasts: continuous or categorical?

The importance of pitch range variation for intonational meaning and theory is well known; however, whether pitch range is a phonetic dimension which is treated categorically in English remains unclear. To test this possibility, three intonation continua varying in pitch range were constructed which had endpoints with contrastive representations under autosegmental-metrical (AM) theory: H* vs. L+H*, H* with 'peak delay' vs. L*+H, and %H L* vs. L*. The prediction derived from AM theory was that the reproduction of continuous pitch range variation should show a discrete pattern reflecting a change in the phonological representation of tonal sequences and in the number of tonal targets across each continuum. Participants' reproductions of each stimulus set showed continuous variation in pitch range, suggesting that pitch range is a gradient phonetic dimension in English conveying semantic contrast, similar to the formant space for vowels. Moreover, the gradience observed in productions across all parts of the pitch range suggests that contours within each series had the same number of tonal targets. The results support a version of AM theory in which rises and falls are usually comprised of two tonal targets, with strictly monotonic f(0) interpolation between them.