Speech Rhythm and Speech Rate in Crosslinguistic Comparison

It is widely accepted that languages can be classified into (two or) three rhythm classes: Stress-timed (e.g. Dutch, English), syllable-timed (e.g. Italian, Spanish), or moratimed (Japanese). But it is difficult to set out clear rules for assigning a language to such categories. After the rejection of the isochrony hypothesis, recent work (e.g. Ramus 2002) mainly focuses on durational patterns of vocalic and intervocalic intervals and their variability. In this paper Ramus suspects that differences in rhythm might be closely related to differences in speech rate but that it is “almost illusory” to find a valid measure of speech rate across languages. Roach (1998) argues that the n of syllables is a much more reliable measure than the number of words, but that one “should bear in mind that different languages have very different syllable structures”. Is it useful to include the problematic variable “speech rate”?