ABSTRACT
Partly due to political pressure within academic institutions to establish intellectual and funding independence, and partly due to a concern that the knowledge base should be as secure as possible, applied linguists have developed careful and even sophisticated notions of what kind of theory and what kind of research data and analysis methods are appropriate for the discipline. Today, these are the subject of vigorous debate, centring on the twin problems of just what a theory of second language acquisition and performance, or of teaching languages, or of any other content area within the discipline should be able to explain and predict, and of how the nature of the relationship between research and action, essentially the practice of language teaching, testing, planning, training and so on, should be codified. This chapter looks at each of these problems under four general headings: knowing a language; practice and theory; the nature of theory; and research traditions.
