Linguistics is the scientific study of spoken language. Different branches of linguistics deal with the development of languages over time; the structures of languages; the descriptions of different languages at a particular time; the physical and mental factors involved in the production of speech and use of language; and the study of meaning (semantics). Applied linguistics makes use of the discoveries of other areas of linguistics to deal with practical problems, in particular language teaching and the deduction of information about a culture, past or present, from the language that it uses.