Complementizer
In linguistics (especially generative grammar), a
complementizer (or
complementiser) is a lexical category (part of speech) including those words that can be used to turn a clause into the subject or object of a sentence. For example, the word
that is generally called a complementizer in English sentences like
Mary believes that it is raining.
Complementizer is a technical term in linguistics; in traditional grammar, such words are normally considered conjunctions. The standard abbreviation for
complementizer is
C. The complementizer is widely held to be the syntactic head of a full clause, which is therefore often represented by the abbreviation
CP (for
complementizer phrase). Evidence that the complementizer functions as the head of its clause includes the fact that it is commonly the last element in a clause in languages like Korean or Japanese, in which other heads follow their complements, and always first in "head-initial" languages such as English. It is common for the complementizers of a language to develop historically from other syntactic categories (a process known as grammaticalization).