The largest structural unit in terms of which the grammar of a language is organized. Most linguistic definitions of the sentence show the influence of Leonard Bloomfield, who pointed to the structural autonomy, or independence, of the notion of sentence: it is ‘not included by virtue of any grammatical construction in any larger linguistic form’. Linguistic discussion of the sentence has focused on problems of identification, classification and generation. Identifying sentences is relatively straightforward in the written language, but is often problematic in speech, where intonation and pause may give uncertain clues as to whether a sentence boundary exists. Classification of sentence structure proceeds along many different lines, e.g. the binary constituent procedures of immediate-constituent analysis, or the hierarchical analyse of Hallidayan and other grammars. Most analysts agree on the need to recognize a functional classification of sentences into statement, question, command and exclamatory types. There is also widespread recognition of a formal classification into declarative, interrogative, imperative and exclamative types.