Underspecification

Definition
Underspecification is the theory that underlying representations are not fully specified i.c. that predictable information is not underlyingly present.

Example
In English there is no lexical distinction between aspirated and non-aspirated stops. Still there is a phonetic difference between the [p^h] in [p^h]in and the non-aspirated [p] in s[p]in. Underspecification theory expresses this by assuming that underlyingly both p's are not specified for aspiration. The aspiration feature is later (post-lexically) specified by a context-sensitive rule inserting [+spread glottis] at the beginning of a syllable; the non-aspiration is a consequence of a universal rule which inserts [-spread glottis] in all other contexts. See Structure preservation, structure-building rule.

Links

 * Utrecht Lexicon of Linguistics