Verb

Valency

The number of arguments that a verb takes is called its valency, or valence. According to valency, a verb can be classified as one of:

• 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 rabbits".
• 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 flowers to me".

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

• I gave. (intransitive)
• I gave blood. (transitive)
• I gave blood for John. (ditransitive)

In many languages other than English, such valency changes aren't possible like this; the verb must instead be inflected for voice in order to change the valency.

Copula

A copula is a word that is used to describe its subject, or to equate or liken the subject with its predicate. In many languages, copulas are a special kind of verb, sometimes called copulative verbs or linking verbs.

Because copulas do not describe actions being performed, they are usually analysed outside the transitive/intransitive distinction. The most basic copula in English is to be; there are others (remain, seem, grow, become, etc.).

Some languages (the Semitic family, Russian, Chinese, Sanskrit, and others) can omit the simple copula equivalent of "to be", especially in the present tense. In these languages a noun and adjective pair (or two nouns) can constitute a complete sentence. This construction is called zero copula.

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 give is giving, and the passive participle is given. The active participle describes nouns that are wont to do the action given in the verb, e.g. a giving person. The passive participle describes nouns that have been the subject of the action of the verb, e.g. given money. Other languages apply tense and aspect to participles, and possess a larger number of them with more distinct shades of meaning.

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 inflects verbs for tense/mood/aspect and they agree in person and number (but not gender) 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.

See also

• Linguistics, grammar, syntax, phrase structure rules
• Tense, aspect, mood, voice
• Verb framing
• English verbs
• Irregular verb
• Reflexive verb
• Auxiliary verb
• Light verb
• Le Train de Nulle Part: A 233-page book without a single verb.