Abstract

An accumulating body of experimental evidence shows that detailed acoustic patterns systematically indicate not just the phonological structure of citation-form lexical items, but also a wealth of other linguistic and interactional information. Listeners learn about these cues to the meaning of utterances, use them to understand meaning in at least some conditions, and can adapt rapidly to their statistical distribution. Such systematic patterns are widespread in normal speech, but some are rarer in standard read ‘laboratory speech’. Some of the distinctions are easy to hear, others are very hard to hear but nevertheless influence perceptual decisions, especially under adverse listening conditions such as in noise (when, interestingly, they would be expected to be even harder to hear). Some seem to have relatively restricted linguistic functions, while others have multiple linguistic functions. One implication is that understanding speech involves identification of many different types of unit, none of which is primary, and all of which may feed off one another. This and other evidence supports the claim that speech sounds can be mapped onto any level of linguistic structure, in parallel or in sequence, using context-dependent probabilistic processes. If this is the case, then the process of speech perception is governed by the properties of the particular signal in conjunction with the listener’s construal of the particular situation: thus understanding how speech is processed requires understanding the context, the task, and the listener’s past experience and current expectations. These and other points raise questions about the status of theoretical constructs such as the mental lexicon. To account for the plasticity and task-oriented use of phonetic detail, a fundamental issue may be whether conceptualisation of ‘static’ linguistic structure should be replaced by a function- or process-oriented framework. For speaker-hearers, this may mean that linguistic knowledge is not necessarily distinct from other knowledge, but essentially embodied, and constantly in flux.