In theoretical linguistics, underspecification is an analytic strategy in which a linguistic representation omits the value of one or more features, leaving those values to be supplied by general principles (e.g. redundancy rules, harmony, default inheritance, or constraint interaction).
The term is used in phonology and phonetics for segmental and suprasegmental features,
and in computational semantics and natural-language processing for representing ambiguities (especially scope) without committing to a fully resolved reading (“scope underspecification”).
Phonology
In phonology, underspecification is often used to distinguish contrastive from predictable feature values in underlying representations. Predictable values may be supplied by redundancy/defaults or by processes such as assimilation and harmony, helping capture patterns over natural classes without listing every feature value in the lexicon.
Approaches
Restricted underspecification holds that features should be underspecified only when their values are predictable from general principles (i.e. redundant or non-contrastive in a given context).
Radical underspecification allows traditionally binary features to be lexically specified for only one value (often the marked value), with the opposite value supplied by default when no specification is present.
{| class="wikitable"
|+ Surface realizations of an underspecified high vowel
A common illustration in inflectional morphology comes from syncretic paradigms in languages such as German. German determiners, adjectives, and nouns show extensive syncretism across case, number, and gender, and the definite-article paradigm illustrates this pattern:
{| class="wikitable"
|+ German definite articles
! rowspan="2" |
! colspan="3" | Singular
! rowspan="2" | Plural
|-
! Masc.
! Fem.
! Neut.
|-
! Nominative
| der
| die
| das
| die
|-
! Genitive
| des
| der
| des
| der
|-
! Dative
| dem
| der
| dem
| den
|-
! Accusative
| den
| die
| das
| die
|}
The paradigm exhibits syncretism, with the same surface form realizing multiple case–number–gender combinations; Die occurs in several nominative/accusative and plural cells, and der occurs in genitive/dative feminine as well as genitive plural.
In one proposal, German gender is represented using the binary features [±masc] and [±fem], with neuter analyzed as [−masc, −fem] and the combination [+masc, +fem] not used for any gender in the system described.
In constraint-based grammar formalisms, a related notion is feature indeterminacy, where an item can satisfy conflicting requirements because its feature value is not fully determined. This has been studied for case and agreement phenomena, and is sometimes contrasted with (or related to) underspecification depending on the formal machinery adopted.
See also
- Feature structure
- Syncretism
- Scope ambiguity
- Minimal recursion semantics