Verbs

In syntax, a verb is a word (part of speech) that usually denotes an action (bring, read), an occurrence (decompose, glitter), or a state of being (exist, stand). Depending on the language, a verb may vary in form according to many factors, possibly including its tense, aspect, mood and voice. It may also agree with the person, gender, and/or number of some of its arguments (subject, object, etc.).

Valency
The number of arguments that a verb takes is called its valency or valence. Verbs can be classified according to their valency.


 * Intransitive (valency = 1): the verb only has a subject. For example: "he runs", "it falls".
 * Transitive (valency = 2): the verb has a subject and a direct object. For example: "she eats fish", "we hunt deer".
 * Ditransitive (valency = 3): the verb has a subject, a direct object and an indirect or secondary object. For example: "I gave her a book," "She sent me flowers."

It is impossible to have verbs with zero valency. Weather verbs are often impersonal (subjectless) in null-subject languages like Spanish, where the verb llueve means "It rains". In English, they require a dummy pronoun, and therefore formally have a valency of 1.

The intransitive and transitive are typical, but the impersonal and objective are somewhat different from the norm. In this sense you can see that a verb is a person, place, thing, or link. In the objective the verb takes an object but no subject, the nonreferent subject in some uses may be marked in the verb by an incorporated dummy pronoun similar to the English weather verb (see below). Impersonal verbs take neither subject nor object, as with other null subject languages, but again the verb may show incorporated dummy pronouns despite the lack of subject and object phrases. Tlingit lacks a ditransitive, so the indirect object is described by a separate, extraposed clause.

English verbs are often flexible with regard to valency. A transitive verb can often drop its object and become intransitive; or an intransitive verb can take an object and become transitive. Compare:


 * I moved. (intransitive)
 * I moved the book. (transitive)

In the first example, the verb move has no grammatical object. (In this case, there may be an object understood - the subject (I/myself). The verb is then possibly reflexive, rather than intransitive); in the second the subject and object are distinct. The verb has a different valency, but the form remains exactly the same.

In many languages other than English, such valency changes are not possible like this; the verb must instead be inflected for voice in order to change the valency. a verb is an action.

Verbal noun and verbal adjective
Most languages have a number of verbal nouns that describe the action of the verb. In Indo-European languages, there are several kinds of verbal nouns, including gerunds, infinitives, and supines. English has gerunds, such as seeing, and infinitives such as to see; they both can function as nouns; seeing is believing is roughly equivalent in meaning with to see is to believe. These terms are sometimes applied to verbal nouns of non-Indo-European languages.

In the Indo-European languages, verbal adjectives are generally called participles. English has an active participle, also called a present participle; and a passive participle, also called a past participle. The active participle of play is playing, and the passive participle is played. The active participle describes nouns that perform the action given in the verb, e.g. I saw the playing children.. The passive participle describes nouns that have been the object of the action of the verb, e.g. I saw the played game scattered across the floor.

Other languages have attributive verb forms with tense and aspect. This is especially common among verb-final languages, where attributive verb phrases act as relative clauses.

Agreement
In languages where the verb is inflected, it often agrees with its primary argument (what we tend to call the subject) in person, number and/or gender. English only shows distinctive agreement in the third person singular, present tense form of verbs (which is marked by adding "-s"); the rest of the persons are not distinguished in the verb.

Spanish and other Romance languages inflect verbs for tense/mood/aspect and they agree in person and number (but not in gender, as for example in Polish) with the subject. Japanese, in turn, inflects verbs for many more categories, but shows absolutely no agreement with the subject. Basque, Georgian, and some other languages, have polypersonal agreement: the verb agrees with the subject, the direct object and even the secondary object if present.