New Ways of Analyzing Sound Change: Speech Rate Effects

Synchronic and diachronic sound change may involve (1) the phonologization of an effect of phonetic implementation, or (2) the lexicalization of phonetic or phonogical processes. This paper seeks to determine the phonologization and lexicalization of phonetic and phonological effects on the basis of their behaviour across different speaking rates. To illustrate the phonologization of phonetic effects, cross-linguistic data on aspiration and vowel nasalization across different speech rates are presented. The data show that phonological effects adjust to variations in speech rate, so as to keep a constant perceptual distance across rates, whereas phonetic effects, which originate at a lower level, remain constant across rates or present rate-correlated changes which can be accounted for by the general principles of speech motor control. Speech rate might also allow us to distinguish between phonetic effects which do not involve a change in the underlying representation, and effects which have been lexicalized. Connected speech processes, such as assimilation, are known to depend on factors such as speaking rate and speaking style. Consequently, low level assimilatory processes are expected to show continuous variation with changes in rate, as a result of increased gestural overlap. On the contrary, if assimilatory processes have been lexicalized as a distinct lexical representation or as an alternative style-dependent form, then the lexicalized form will exhibit a rate-invariant pattern. A variety of experimental data which provide support for this new way of analyzing sound change is presented. It is argued that part of the synchronic variation in present-day speakers is due to sound change, i.e. a discrete, categorical change in the speaker's grammar.