input (n.)

(1) A term used in PSYCHOLINGUISTICS to refer to the external linguistic DATA available to speakers in the course of acquiring a language. The notion is particularly relevant to child language ACQUISITION of a mother-tongue, where the role of input is related to other factors in learning, such as innate ability; but it also applies in the study of foreign-language learning. The term is also used in language PROCESSING to refer to the signal processed by the listener/reader.

(2) A use of the general sense of this term is found in GENERATIVE GRAMMAR for a linguistic construct which triggers the application of a RULE, either as the starting-point in the generation of a sentence or at a later stage in a DERIVATION. It contrasts with OUTPUT, which may be a derived linguistic construct or (after all rules have been applied) a REPRESENTATION of what people actually say. In this approach, the input to a rule is typically the output of an earlier rule.

(3) In OPTIMALITY THEORY, an input is a linguistic construct, composed from the elements in UNIVERSAL GRAMMAR (consonant, vowel, syllable, noun, verb, etc.), to which OUTPUT REPRESENTATIONS are related. This process takes place through the operation of the GENERATOR and EVALUATOR mechanisms provided by the theory. The optimal input is selected from all possible inputs (corresponding to a single output) as the one which incurs the fewest highest-ranked CONSTRAINT VIOLATIONS. The OT perspective therefore runs contrary to the traditional GENERATIVE approach, for it does not require a unique input for a given output. Any input which results in a correct input–output pairing is a viable input.