Operator (linguistics)

In generative grammar, the technical term operator denotes a type of expression that enters into an a-bar movement dependency. One often says that the operator "binds a variable".

Operators are often determiners, such as interrogatives ('which', 'who', 'when', etc.), or quantifiers ('every', 'some', 'most', 'no'), but adverbs such as sentential negation ('not') have also been treated as operators. It is also common within generative grammar to hypothesise phonetically empty operators whenever a clause type or construction exhibits symptoms of the presence of an a-bar movement dependency, such as sensitivity to extraction islands.

The following examples illustrate the use of the term operator within generative grammatical theory.

The following example is a case of so-called "wh-movement":

Here, "what" is an operator, binding a phonetically empty "variable" indicated here as "__".

In the generative model of the syntax-semantics interface, a quantifier must move to positions higher in the structure, leaving behind a trace which it then binds. When this movement leaves the spoken word order unchanged, it is said to be "covert". This process of covert quantifier raising (QR) can create scope ambiguities as in the following example.

This sentence is ambiguous between an "I did nothing" reading and another, "there's something I didn't do" reading. On the latter reading, one would represent the sentence as follows within generative grammar (omitting irrelevant details):

Here, "x" is the variable, and "something_x" is the operator binding that variable.