Prosody and Segmental Effect Some Paths of Evolution for Word Stress

This study reports on a significant negative association found in a cross-linguistic sample between the degree of predictability of word stress from a word boundary and the extent to which stress has segmental effects. In other words, in a given language the less predictable stress is from the word boundary, the more likely that the language will have vowel reduction in unstressed syllables, vowel lengthening in stressed syllables, and consonantal changes restricted to stressed or unstressed syllables. These findings are interpreted as part of a major diachronic tendency for stressed and unstressed syllables to become more differentiated in terms of duration as a cumulative effect of phonetic change, which in turn leads to the deletion of unstressed syllables, which renders stress unpredictable in some cases. A model of phonological representation that best accounts for the unidirectionality of this strong tendency is one in which stress, even while it is still predictable, is considered an inherent part of the word, and phonetic changes have a permanent and cumulative effect on lexical representation.