Verb

In syntax, a verb is a word that represents some form of action, occurrence, or state of being.

Valency
There are several types of verbs, each with a different kind of valency:


 * An impersonal verb takes no arguments, e.g. It rains . (Although it is technically the subject of the verb, it is only a dummy subject, that is, a syntactic placeholder with no true meaning. No other subject can replace it in this sentence.)
 * An intransitive verb takes one argument, a subject, e.g. He sleeps .
 * A monotransitive verb takes two arguments, a subject and a direct object, e.g. He kicks the ball.
 * A ditransitive verb takes three arguments, a subject, a direct object, and an indirect object, e.g. He gives her a flower.
 * A tritransitive verb takes four arguments, a subject, a direct object, an indirect object, and a fourth object connected by a preposition, e.g. He traded her an apple for an orange.

The verb requires all of these arguments in a well formed sentence, although they can sometimes undergo changes in valency.

For instance, to eat is naturally transitive, as in he eats an apple, but may be reduced to intransivity in he eats. This is called valency reduction.

Verbs that are usually intransive, like to sleep, cannot take a direct object. However, there are cases where the valency of such verbs can be expanded, for instance in He sleeps the sleep of death. This is called valency expansion.

Verb valence can also be described in terms of syntactic versus semantic criteria. The syntactic valency of a verb refers to the number of dependent arguments that the verb can have, while semantic valence describes the thematic relations associated with a verb.

Some languages allow the change of one type of verb to another type of verb with an affix. For this to happen in English, one would need a different verb to change valency.

Verbal Conjugation
Verbs can be conjugated to a lot of various factors. The most common one is the tense/aspect which is known from English and most languages. But verbs can be conjugated according to person (Romance and Slavic languages), Mood, voice and a lot more in a huge net of conjugations.

Polypersonal agreement
In linguistics, polypersonal agreement or polypersonalism is the agreement of a verb with more than one of its arguments (usually up to four). Polypersonalism is a morphological feature of a language, and languages that display it are called polypersonal languages.