Editing Verb (section)

== Valency ==
{{main|Valency (linguistics)}}
The number of arguments that a verb takes is called its ''valency'' or ''valence''. Verbs can be classified according to their valency:
* '''[[avalency|Avalent]]''' (valency = 0): the verb has neither a subject nor an object. Zero valency does not occur in English; in some languages such as [[Mandarin Chinese]], weather verbs like ''snow(s)'' take no subject or object.
* '''[[Intransitive verb|Intransitive]]''' (valency = 1, monovalent): the verb only has a [[subject (grammar)|subject]]. For example: "he runs", "it falls".
* '''[[transitive verb|Transitive]]''' (valency = 2, divalent): the verb has a subject and a [[direct object]]. For example: "she eats fish", "we hunt nothing".
*'''[[Ditransitive verb|Ditransitive]]''' (valency = 3, trivalent): the verb has a subject, a direct object, and an indirect object. For example: "He gives her a flower" or "She gave John the watch."
*A few English verbs, particularly those concerned with financial transactions, take four arguments, as in "Pat<sub>1</sub> sold Chris<sub>2</sub> a lawnmower<sub>3</sub> for $20<sub>4</sub>" or "Chris<sub>1</sub> paid Pat<sub>2</sub> $20<sub>3</sub> for a lawnmower<sub>4</sub>".{{sfn|Jackendoff|2002|p=135}}

=== Impersonal and objective verbs ===
[[Weather verb]]s often appear to be [[impersonal verb|impersonal]] (subjectless, or avalent) in [[null-subject language]]s like [[Spanish language|Spanish]], where the verb ''llueve'' means "It rains". In English, French and German, they require a [[dummy pronoun]] and therefore formally have a valency of 1. As verbs in Spanish incorporate the subject as a TAM suffix, Spanish is not actually a null-subject language, unlike Mandarin (see above). Such verbs in Spanish also have a valency of 1.

Intransitive and transitive verbs are the most common, but the impersonal and '''[[Impersonal verb|objective verbs]]''' are somewhat different from the norm. 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 that used with the English weather verbs. Impersonal verbs in null subject languages take neither subject nor object, as is true of other verbs, but again the verb may show incorporated dummy pronouns despite the lack of subject and object phrases.

=== Valency marking ===
Verbs are often flexible with regard to valency. In non-valency marking languages such as English, a transitive verb can often drop its object and become intransitive; or an intransitive verb can take an object and become transitive. For example, in English the verb ''move'' has no grammatical object in ''he moves'' (though in this case, the subject itself may be an implied object, also expressible explicitly as in ''he moves himself''); but in ''he moves the car'', the subject and object are distinct and the verb has a different valency. Some verbs in English have historically derived forms that show change of valency in some causative verbs, such as ''fall-fell-fallen'':''fell-felled-felled''; ''rise-rose-risen'':''raise-raised-raised''; ''cost-cost-cost'':''cost-costed-costed''.

In valency marking languages, valency change is shown by inflecting the verb in order to change the valency. In [[Kalaw Lagaw Ya]] of Australia, for example, verbs distinguish valency by argument agreement suffixes and TAM endings:
* '''Nui mangema''' "He arrived earlier today" ('''mangema''' today past singular subject active intransitive perfective)
* '''Palai mangemanu''' "They [dual] arrived earlier today"
* '''Thana mangemainu''' "They [plural] arrived earlier today"
''Verb structure:'' '''manga-i-[number]-TAM''' "arrive+active+singular/dual/plural+TAM"
* '''Nuidh wapi manganu''' "He took the fish [to that place] earlier today" ('''manganu''' today past singular object attainative transitive perfective)
* '''Nuidh wapi mangamanu''' "He took the two fish [to that place] earlier today"
* '''Nuidh wapi mangamainu''' "He took the [three or more] fish [to that place] earlier today"
''Verb structure:'' '''manga-Ø-[number]-TAM''' "arrive+attainative+singular/dual/plural+TAM"

The verb stem '''manga-''' 'to take/come/arrive' at the destination takes the active suffix '''-i''' (> '''mangai-''') in the intransitive form, and as a transitive verb the stem is not suffixed. The TAM ending '''-nu''' is the general today past attainative perfective, found with all numbers in the perfective except the singular active, where '''-ma''' is found.