Abstract : This paper will describe an approach to studies of language and communication that has become known as “Activity based Communication Analysis” (ACA). I will also briefly contrast the approach to some other approaches to linguistic interaction. The paper contains the following sections: 1. Conception of language and linguistic interaction - the task of linguistics 2. On methodology and goals 3. Analytical categories to be used in the study of linguistic interaction 4. On the relation to some other approaches 5. Examples of some studies There are many sources of inspiration for the approach, such as Malinowski (1923), Wittgenstein (1953), Vygotsky (1978), Sacks (1992), Bühler (1934 ), Rommetveit (1974), Grice (1975), Austin (1962) and Firth (1957). For a more extensive account, see Allwood (1976 and 2000).