User:Drmies/sandy boxie

In grammar, a complement is a word or phrase dependent on another word of phrase. This dependence is such a strong relationship that one speaks of words such as verbs, nouns, and prepositions licensing another word, phrase, or clause. In other words, the complement and its grammatical structure depend on the syntactic qualities of the word that licenses it, and some complements are syntactically required. Thus it contrasts sharply with an adjunct, which has a much looser relationship with the words or phrases it modifies.

Perhaps the best-known example of a complement is the object in clause structure, which in a canonical sentence is dependent on the main verb: Sue gave Max the photo. In this case, the verb give licenses a direct object (the photo) and an indirect object (Max). All objects are complements, but not all complements are objects. Besides verbs, other categories of words that can license complements include nouns and prepositions.

Description
A general definition is offered by Rodney Huddleston and Geoffrey K. Pullum: a complement is "a kind of dependent that must be licensed by the head"--a dependent being an "element in...a phrase or clause other than the head".

The most easily identifiable complement is the object, which functions as a complement of a transitive verb. The noun (or noun phrase) is most commonly cited as a complement: Annie bought her sister a new frock. However, there are many other types of complements, found in many other relationships than verb-object.

Two other common complements are the subject complement and the object complement (both are also referred to as "predicative complement"). The subject complement follows a "linking verb" (or copula): The country became totally independent, where "totally independent" is an adjective phrase licensed by become and denotes a quality of the subject ("the country"). The object complement ascribes a quality to the object: Most people considered Picasso a genius, where "a genius", a noun phrase, denotes a quality of the object ("Picasso"). The verb consider licenses an object and a complement. Subject and object complements can come from a wide range of categories--adjective phrases, noun phrases, prepositional phrases.

Complement clauses
Complement clauses are clauses (either finite or non-finite) functioning as complements. All must be licensed (in the examples below by the verb), and the grammar of the complement itself is mandated by the licensing word.


 * Alice wants [to come to the party] - infinitival clause
 * Joyce enjoys [going to the theater] - gerund clause
 * Fred knows [that he must finish the paper] - relative, or content, clause
 * I don't know [how he does it] - interrogative clause

That the verb want, for instance, dictates the grammar of the complementing clause is clear: an infinitival clause is required, a gerund clause (*Alice wants coming to the theater) is ungrammatical.

Traditional definition
Traditional grammars frequently define a complement as that which is necessary "to complete the meaning of the sentence" or "to complete the meaning of the verb". In The principal gave the student a warning, the complement, such grammars instruct, is found by asking "to whom" or "what": "The principal gave what to whom?"

However, such a semantic definition ("semantic" because it invokes the concept of meaning) is clearly fraught with difficulty. Many ditransitive verbs (verbs which license two objects) function just as well with only one object: in Sue gave Max the photo, for instance, Max (indirect object) can easily be left out with a grammatically correct sentence remaining. Likewise, many monotransitive verbs (which license one object) can function without any object: Sue ate bread is as grammatical as Sue ate.

Theoretical background
The Routledge Dictionary of Language and Linguistics defines complement thusly:"A constituent X is a complement of a constituent Y, if X is valence-dependent on Y."The term "valence-dependent" refers to the concept of valency (a term borrowed from the chemical term "valence"), which is the ability of words like verbs, adjectives, and nouns to impose certain requirements on their syntactic environment, in this case to license or dictate certain types of complements. This linguistic terminology finds its origin in Lucien Tesnière's Éléments de syntaxe structurale (1959).