The purpose of this essay is to give an overview of issues related to the processes behind, and linguistic impact of various types of contact between languages and language users, to what happens when languages/language users come into contact, and when they are (not) in contact. While paying specific attention to issues directly relevant to pragmatics, the exposition will provide a fairly general survey of existing research on language-contact phenomena, with an attempt to present the — often implicit — large-scale framework of study in this field. The various terms used for language-contact phenomena and processes will be introduced. The term ‘contact linguistics’ has also sometimes been used in a slightly narrower sense than in the title of this essay, where it is to designate all linguistic approaches to contact. The presentation of the different (socio-)linguistic approaches to language contact, and of the variety of phenomena that are documented to be involved in cases of language contact will be organized under three headings: the location, the direction, and the process of contact. But first the study of language contact will be located more broadly with respect to approaches concerned with the typology and classification of languages.