Word stress in speech perception

In languages with word-level stress, segmentally matched stressed and unstressed syllables (such as the first syllables of English camper and campaign) differ acoustically, but these suprasegmental acoustic differences are not necessarily exploited in speech perception. If word stress position is fixed, stress can help locate boundaries between words, but can play no role in identifying words (for instance, no minimal pairs such as trusty/trustee could then exist). If word stress placement is variable, it can in principle help in word recognition; but whether or not it is actually used depends on vocabulary structure, in particular on the amount of short-term competition between similar-sounding words. This can vary even between closely related languages in which suprasegmental distinctions have been shown to be equally perceptible. Suprasegmental information is only exploited for word recognition in those languages where using it significantly reduces the amount of lexical competition, and hence noticeably speeds lexical processing.