In the 1950s, structural linguistics had developed in part as a reaction to traditional grammar. The scientific approach to the study of language was thought to consist of collecting examples of what speakers said and analyzing them according to different levels of structural organization rather than according to categories of Latin grammar. A sophisticated methodology for collecting and analyzing data developed, which involved transcribing spoken utterances in a language phonetically and later working out the phonemic, morphological and syntactic systems underlying the grammar of the language. Language was viewed as a system of structurally related elements for the encoding of meaning, the elements being phonemes, morphemes, words, structures, and sentence types. The term structural referred to these characteristics: (a) Elements in a language were thought of as being linearly produced in a rule-governed way. (b) Language samples could be exhaustively described at any structural level of description. (c) Linguistic levels were thought of as systems within systems—that is, as being pyramidally structured; phonemic systems led to morphemic systems, and these in turn led to the higherlevel systems of phrases, clauses and sentences.

   Learning a language, it was assumed, entails mastering the elements of building blocks of the language and learning the rules by which these elements are combined, from phoneme to morpheme to word to phrase to sentence. The phonological system defines those sound elements that contrast meaningfully with one another in the language, their phonetic realizations in specific environments, and their permissible sequences. The phonological and grammatical systems of the language constitute the organization of language and by implication the units of production and comprehension. The grammatical system consists of a listing of grammatical elements and rules for their linear combination into words, phrases, and sentences. Rule-ordered processes involve addition, deletion, and transposition of elements.