This paper is available for the academic year 2022-23.

While linguistics often treats language as a phenomenon in its own right, taking its evidence from what people say and what they regard as grammatical, language is clearly also both a cognitive phenomenon (involving the mind and brain), and a social phenomenon (reflecting and indeed reinforcing structures in society). This paper provides an introduction to relation of language to both these domains.

Much of our knowledge about language and the mind is indirect. Although recently it has become possible, through brain-scanning techniques, to see neural responses to different linguistic stimuli, our knowledge from this kind of source is still in its infancy. Much more has been inferred about how the mind organises language from more accessible sources such as language acquisition, speech errors, and language impairment. The acquisition of language by babies and children gives a window on how we seek general patterns (children will over-generalise for while and try forms like goed once they've realised that -ed signals the past tense); and arguably acquisition gives evidence for humans being born with an innate preparedness for language. Errors in producing language turn out not to be random: the fact that tip of the slongue is a much more likely error for slip of the tongue than tlip of the songue shows thatphonotactic constraints are psychologically real (English doesn't allow tl initially in a syllable). And the loss of specific aspects of language after brain damage (e.g. strokes), such as word-finding, or sentence-formation, suggests a degree of modularity in the mind corresponding (in these cases) to the lexicon or to syntax.

Within society, language reflects both geographical and social groups. Non-linguists are well aware of this, for instance describing people as having 'a Yorkshire accent' or 'a posh voice'; but linguistics aims at a precise description of the phonetic, grammatical, lexical, and semantic variables which differentiate accents and dialects. The study of language in society is sociolinguistics. Sometimes this term implies a rather general approach to discourse in society, for instance in the political context, but in this paper the focus will be on patterns of variation in the structure of language. Speakers have an impressive passive knowledge of such variation, which they can use to make linguistic judgments about others; and they can often vary their own speech along similar lines to match their style of speaking to the context. Such variation also often arises from, and drives, the spread of new linguistic features, and this connection will be explored.