default (n.)

The application of the general use of this term in several domains of linguistics and phonetics, to refer to cases where a previously specified value is automatically introduced into an analysis when certain conditions apply. In some models of PHONOLOGY, for example, it refers to an UNMARKED mode of operation of a RULE. A case in point is in radical UNDERSPECIFICATION theory, where for each FEATURE one value (the phonologically active value) is specified in the lexical REPRESENTATION, and the other is filled in at some later stage by a default rule (DR, or default specification) which assigns an unmarked value to the feature. The default rule may become activated by a phonological rule, or it may stay passive throughout the derivation. The notion is also important in MORPHOLOGY, where a particular ALLOMORPH can be viewed as a default form (e.g. the -ed past-tense ending in English) and in some SEMANTIC lexical analyses, such as certain models of TYPED FEATURE structures.