- Control verb
linguistics, a control verb (also called an "equi" verb) is a verbthat combines with (at least) one nominal complement and one verbal complement, such that the nominal complement corresponds to a semantic argumentof both the control verb and its verbal complement. For example, in the English example "George tried to escape", "tried" is a control verb. Its syntactic subject "George" must be interpreted as the agent argument of both "tried" and "to escape".
Control and raising verbs
The term "control verb" is sometimes generalized somewhat to include
raising verbs, which are much the same, except with a noun argument being semantically an argument "only" of the verb argument, "not" of the raising verb itself. For example, in "He seemed to do that," "seemed" is a raising verb, where its subject "he" is semantically the subject of "to do" rather than of "seemed". (Note that one could say, "It seemed that he did that," but not, *"It tried that he did that." Similarly, one could say, "That seemed to be done by him," but "That tried to be done by him" would be syntactically well-formed but would have a different, nonsensical meaning.)
As with many technical terms, both "control verb" and "raising verb" are used somewhat differently in different papers, partly because different linguistic theories may group verbs in somewhat different hierarchies.
Object- and subject-control verbs
In English and many other languages, control verbs may be classified as either "subject-control", meaning that it is their (syntactic) subject that is semantically shared, or "object-control", meaning that it is their (syntactic) object that is. For example, "try" is subject-control (as seen above), while "convince" is object-control: in "She convinced him to do that," "him" is syntactically only the direct object of "convinced", but semantically both the patient of "convinced" and the agent of "to do".
Note that a verb may be subject-control in one sentence and object-control in another. For example, in "She asked to be left alone," "asked" is subject-control, while in "She asked him to leave her alone," "asked" is object-control. Generally, when such a verb takes an object, it is implied that it is acting as an object-control verb; for example, speakers of English would likely find a bit odd the sentence "She asked him to be allowed to stay" (with the intended meaning of "She asked him for permission to stay"), initially attempting to interpret it as "She asked of him that he be allowed to stay," but they would likely understand it after a moment.
Control Theory in Government and Binding
In the GB framework the above-mentioned sentence is analysed as follows:
*He tried [CP PRO to do that]
The existence of PRO (Spec-IP in the embedded clause) is required by the
Extended Projection Principle, which says that all clauses must have a subject. The main characteristic feature of PRO is that it must be ungoverned (the PRO Theorem). In terms of features it is [+anaphor, +pronominal] (see Binding (linguistics)). That is why such sentences as *"I expect [John to meet PRO] " are ungrammatical: PRO would be theta-governed by the verb.
The expletive test (using non-referential "there" or "it") helps to distinguish between object-control and other types of verbs:
*"persuade": an object-control verb taking a CP complement
**I persuaded John [CP PRO to read the book]
** *I persuaded [there to be a problem]
** *I persuaded [it to rain]
**I expected [IP John to read the book]
**I expected [there to be a problem]
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