LEVEL OF LANGUAGE. A term in (structural) LINGUISTICS. In the second quarter of the 20c, language was modelled by some linguists as a series of layers arranged one on top of the other, with units of sound (PHONOLOGY) on the bottom layer, gathered into units of structure (MORPHOLOGY) above, which were then combined into larger grammatical units (SYNTAX) above them, and, according to some, into units of meaning (SEMANTICS) at the top. The two lowest levels each had a unit of its own, formed with the suffix -EME: PHONEME for phonology, MORPHEME for morphology. In some theories, this approach continued upwards with lexeme for an abstract lexical unit, and tagmeme sometimes used for syntax. The term has come into widespread, fairly loose usage to mean any one such layer: the phonological level, the syntactic level, etc. Originally, each level was studied independently of the others, at least in theory, and it was considered necessary to work from phonology upwards, finishing the study of one level before moving on to the next. A number of introductory textbooks of linguistics are organized in accordance with this model, which is still of value, although the strict separation of levels is no longer adhered to. In recent years, some linguists have tended to abandon the vertical ‘layer cake’ model in favour of a horizontal model with a syntactic component flanked by a phonological component on one side and a semantic component on the other. Syntax has this central role because it can be regarded as the component that links sound and meaning.