Passive voice is a grammatical voice common in many of the world's languages. In a clause with passive voice, the grammatical subject expresses the theme or patient of the main verb – that is, the person or thing that undergoes the action or has its state changed. This contrasts with active voice, in which the subject has the agent role. For example, in the passive sentence "The tree was pulled down", the subject (the tree) denotes the patient rather than the agent of the action. In contrast, the sentences "Someone pulled down the tree" and "The tree is down" are active sentences.
Typically, in passive clauses, what would otherwise be expressed by the object (or sometimes another argument) of the verb comes to be expressed by the subject, while what would otherwise be expressed by the subject is either not expressed at all, or is indicated by some adjunct of the clause. Thus transforming an active verb into a passive verb is a valence-decreasing process ("detransitivizing process"), because it transforms transitive verbs into intransitive verbs.
Many languages have both an active and a passive voice; this allows for greater flexibility in sentence construction, as either the semantic agent or patient may take the syntactic role of subject. The use of passive voice allows speakers to organize stretches of discourse by placing figures other than the agent in subject position. This may be done to foreground the patient, recipient, or other thematic role; it may also be useful when the semantic patient is the topic of on-going discussion. The passive voice may also be used to avoid specifying the agent of an action.
Passive marking 
Different languages use various grammatical forms to indicate passive voice.
|Vīnum (ā) servō portātur.||Vinet bärs av tjänaren.||"The wine is carried by the servant." (passive voice)|
|Servus vīnum portat.||Tjänaren bär vinet.||"The servant carries the wine." (active voice)|
In Latin, the agent of a passive sentence (if indicated) is expressed using a noun in the ablative case, in this case servō (the ablative of servus). Different languages use different methods for expressing the agent in passive clauses. In Swedish, the agent can be expressed by means of a prepositional phrase with the preposition av (equivalent here to the English "by").
The passive voice in English 
English, like some other languages, uses a periphrastic passive. Rather than conjugating directly for voice, English uses the past participle form of the verb plus an auxiliary verb, either be or get, to indicate passive voice.
- The money was donated to the school.
- The vase got broken during the fight.
- All men are created equal.
If the agent is mentioned, it usually appears in a prepositional phrase introduced by the preposition by.
- Without agent: The paper was marked.
- With agent: The paper was marked by Mr. Tan.
The subject of the passive voice usually corresponds to the direct object of the corresponding active voice (as in the above examples), but English also allows passive constructions in which the subject corresponds to an indirect object or preposition complement:
- We were given tickets. (subject we corresponds to the indirect object of give)
- Tim was operated on yesterday. (subject Tim corresponds to the complement of the preposition on)
In sentences of the second type, a stranded preposition is left. This is called the prepositional passive or pseudo-passive (although the latter term can also be used with other meanings).
The active voice is the dominant voice in English at large. Many commentators, notably George Orwell in his essay "Politics and the English Language" and Strunk & White in The Elements of Style, have urged minimizing use of the passive voice. However, the passive voice has important uses. Jan Freeman of The Boston Globe states "[a]ll good writers use the passive voice" – including Orwell and Strunk & White themselves, in the sections of their essays criticizing the passive voice. There is general agreement that the passive voice is useful for emphasis, or when the receiver of the action is more important than the actor.
Adversative passive 
Some languages, including several Southeast Asian languages, use a form of passive voice to indicate that an action or event was unpleasant or undesirable. This so-called adversative passive works like the ordinary passive voice in terms of syntactic structure—that is, a theme or instrument acts as subject. In addition, the construction indicates adversative affect, suggesting that someone was negatively affected.
The Japanese adversative passive (also called indirect passive) indicates adversative affect.
- 花子が 隣の 学生に ピアノを 朝まで 弾かれた。
- Hanako-ga tonari-no gakusei-ni piano-o asa-made hikareta.
- Hanako-subject neighbor student-by piano-object morning-until played-passive
- "Hanako was adversely affected by the neighboring student playing the piano until morning."
The indirect or adversative passive has the same form as the direct passive in Japanese. Unlike the direct passive, the indirect passive may be used with intransitive verbs.
Stative and dynamic passive 
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In languages such as English, there is often a similarity between passive clauses expressing an action or event, such as:
- The dog is fed (every day)
and clauses expressing a state, such as:
- The dog is fed (for now).
In the first sentence the auxiliary is and the past participle fed combine to express the verbal passive voice, while in the second sentence is serves as an ordinary copula and the past participle as an ordinary adjective.
Sentences of the second type are sometimes confused with the passive voice, and in some treatments are considered to be a type of passive – a stative or static passive, in contrast to the dynamic or eventive passive exemplified by the first sentence. The stative type may also be called false passive. Some languages express or can express these meanings in contrasting ways.
Static passive auxiliary verb: sein ("sein-Passiv, Zustandspassiv")
Dynamic passive auxiliary verb: werden ("werden-Passiv")
- Der Rasen ist gemäht ("The lawn is mown", static)
- Der Rasen wird gemäht ("The lawn is being mown", literally "The lawn becomes mown", dynamic)
A number of verbs such as bedecken "cover", erfüllen "fill", trennen "separate", when used as stative verbs, only form static passives:
- Schnee bedeckt die Erde ("Snow covers the earth", active)
- Die Erde ist von Schnee bedeckt ("The earth is covered in snow", static)
- but not: *Die Erde wird von Schnee bedeckt (dynamic)
Passive voice expressed with the auxiliary verb get rather than be ("get-passive") tends to express a dynamic rather than a static meaning in English. When the auxiliary verb be is used, the main verb may have either a dynamic or static meaning.
- The couple got married last spring. (dynamic)
- The marriage was celebrated last spring. (dynamic)
- It is agreed that laws were invented for the safety of citizens. (stative)
Verbs that typically express static meaning can show dynamic meaning when expressed as a get-passive, as with be known (static) vs. get known (dynamic).
- Zoltan is known for hosting big parties. (static)
- Get your foot in the door, get known. (dynamic)[unreliable source?]
Static passive auxiliary verb: vara (är, var, varit)
Dynamic passive auxiliary verb: bli (blir, blev, blivit) Dynamic passive in Swedish is also frequently expressed with the s-ending.
- Dörren är öppnad. "The door has been opened."
- Dörren blir öppnad. "The door is being opened."
The vara passive is often synonymous with, and sometimes preferable to, simply using the corresponding adjective:
- Dörren är öppen. "The door is open."
The bli passive is often synonymous with, and sometimes preferable to, the s-passive:
- Dörren öppnas. "The door is opening."
Italian uses two verbs (essere and venire) to translate the static and the dynamic passive:
Dynamic passive auxiliary verb: essere and venire (to be and to come)
- La porta è aperta. or La porta viene aperta. "The door is opened [by someone]" or "The door comes open [by someone]".
- La porta è chiusa. or La porta viene chiusa. "The door is closed [by someone]" or "The door comes closed [by someone]".
Static passive auxiliary verb: essere (to be)
- La porta è aperta. "The door is open," i.e. it has been opened.
- La porta è chiusa. "The door is closed," i.e. it has been closed.
In Venetian (Vèneto) the difference between dynamic (true) passive and stative (adjectival) passive is more clear cut, using èser (to be) only for the static passives and vegner (to become, to come) only for the dynamic passive:
- Ła porta ła vien verta. "The door is opened", dynamic
- Ła porta ła xè / l'è verta. "The door is open", static
Static forms represents much more a property or general condition, whereas the dynamic form is a real passive action entailing "by someone":
- èser proteto. "To be protected = to be in a safe condition", static
- vegner proteto. "To be protected = to be defended (by so)", dynamic
- èser considarà. "To be considered = to have a (good) reputation", static
- vegner considarà. "To be taken into consideration (by people, by so)", dynamic
- èser raprexentà (a l'ONU). "To be represented (at the UN) = to have a representation", static
- vegner raprexentà a l'ONU (da un dełegà). "To be represented at the UN (by a delegate)", dynamic
See also 
- O'Grady, William, John Archibald, Mark Aronoff, and Janie Rees-Miller (eds.) (2001). Contemporary Linguistics: An Introduction Fourth edition. Boston: Bedford/St. Martin's. ISBN 0-312-24738-9
- Paul Kroeger, Analyzing grammar: an introduction, Cambridge University Press, 2005, ISBN 052181622X, p. 272
- Saeed, John (1997). Semantics. Oxford: Blackwell. ISBN 0-631-20035-5
- Croft, William (1991). Syntactic Categories and Grammatical Relations: The Cognitive Organization of Information. Chicago: University of Chicago Press. ISBN 0-226-12090-2
- Kroeger, Paul. 2005. Analyzing Grammar: An Introduction. Cambridge: Cambridge University Press. ISBN 0-521-81622-X
- Freeman, Jan (2009-03-22). "Active resistance: What we get wrong about the passive voice". The Boston Globe (Boston). ISSN 0743-1791. Retrieved 2010-03-01. "All good writers use the passive voice."
- Webster's Dictionary of English Usage, pp.720–21 (1989).
- Tsujimura, Natsuko. 1996. An Introduction to Japanese Linguistics. Oxford: Blackwell. ISBN 0-631-19855-5
- Grebe, Paul, ed. (1973). Die Grammatik der deutschen Gegenwartssprache [Grammar of the contemporary German language] (3rd ed.). Mannheim: Dudenverlag. pp. 91–95. ISBN 3-411-00914-4.
- Knabe, Norman (January 2009). The Get-Passives as an Emotive Language Device. GRIN Verlag. ISBN 978-3-640-25174-2. Retrieved 13 November 2012.