Phonetics and phonology are among the branches of linguistics with least impact on applied linguistics. This is unfortunate, as they have a great deal to oﬀer research and teaching in the many applications that investigate the production, understanding or representation of speech, especially second language teaching, which will be the focus of this chapter. One reason for their lack of impact might be that they are often perceived as highly com-
plicated topics, dominated by theoretical issues of limited relevance to practical applications. It is useful in this regard to invoke a distinction between ‘complicated’ and ‘complex’. A simple system has few parts, related by a small enough number of rules as to be easily understood by the average person. A complicated system is quantitatively diﬀerent, with many more parts, related by more numerous, more inter-related rules. A complex system is qualitatively diﬀerent, with larger, less clearly deﬁned parts, connected by a smaller number of general, context-dependent principles (Ellis, this volume). Working eﬀectively with either kind of system requires recognition of which kind it is.
However, since their products can seem superﬁcially similar, it is possible to confuse them, with unfortunate results (Westley et al. 2006). The argument of this chapter is that speech is a complex system, but most current theories of phonetics and phonology model it as a complicated system. While this is appropriate for some applications, for others, a theoretical framework which recognises the complex nature of speech is needed. One problem is that understanding speech as a complex system means revising basic ideas
in ways that challenge not just existing academic theories, but apparently obvious facts about speech. The intention here, however, is not to contradict existing ideas, but to place them in a wider context, with the aim of encouraging cross-fertilisation between branches of theoretical and applied research that have had too little contact in recent decades. The chapter begins by reviewing some well-known observations, and equally well-known
misconceptions, about speech. It then provides a simple analogy as a basis for understanding and comparing diﬀerent views about speech, and goes on to use the analogy in an interpretive overview of the historical development of phonetics and phonology in relation to applied linguistics. Discussion then turns to how the knowledge acquired by phonetics and phonology
can be framed in a way that allows fruitful, two-way interaction with various branches of applied linguistics, especially sociocognitive theories of second language teaching.