Prenasalized stops and speech timing.

Abstract

Prenasalized stops, that is, homorganic nasal+stop elements that behave as single phonological segments, raise a number of interesting questions concerning the relationship between phonological units and timing in speech. Do complex phonetic elements of this kind occupy the same duration as simpler elements, such as plain stops or nasals? Do prenasalized stops have the same timing pattern as a phonological sequence of nasal plus stop? How do prenasalized stops act with respect to rules which adjust the duration of neighboring segments? For example, would a vowel before a prenasalized stop be shortened by the widespread rule which shortens a vowel in a closed syllable (Maddieson 1985)? It has been argued that the status of prenasalized stops as single segments is directly related to their duration. They have been defined as nasal+stop sequences with the duration typical of other single segments (Herbert 1986). He, and Sagey (1986), in her dissertation on complex segments, both indicate that they would expect phonological consonant sequences to have longer durations than single segments regardless of whether the single segments are phonetically simple or complex. On the other hand, Ladefoged and Maddieson (1986) suggest that there is no demonstrated phonetic difference in timing between nasal+stop sequences and prenasalized stops. Purported language-internal contrasts between these elements actually involve a difference between geminate and single nasals before stops (as in Sinhalese), or between syllabic and non-syllabic nasals before stops. They suggest that deciding if a nasal+stop element is a prenasalized stop is not a phonetic issue but one which concerns solely the phonology of the language in question.