Anticausative verb

An anticausative verb (abbreviated ) is an intransitive verb that shows an event affecting its subject, while giving no semantic or syntactic indication of the cause of the event. The single argument of the anticausative verb (its subject) is a patient, that is, what undergoes an action. One can assume that there is a cause or an agent of causation, but the syntactic structure of the anticausative makes it unnatural or impossible to refer to it directly. Examples of anticausative verbs are "break", "sink", "move", etc.
Anticausative verbs are a subset of unaccusative verbs. Although the terms are generally synonymous, some unaccusative verbs are more obviously anticausative, while others ("fall", "die", etc.) are not; it depends on whether causation is defined as having to do with an animate volitional agent (does "falling" mean "being accelerated down by gravity" or "being dropped/pushed down by someone"? Is "old age" a causation agent for "dying"?).
A distinction must be made between anticausative and autocausative verbs. A verb is anticausative if the agent is unspecified but assumed to be external (or even if its existence is denied), and it is autocausative if the agent is the same as the patient. Many Indo-European languages lack separate morphological markings for these two classes, and the correct class needs to be derived from context:
Examples.
English.
In English, many anticausatives are of the class of "alternating ambitransitive verbs", where the alternation between transitive and intransitive forms produces a change of the position of the patient role (the transitive form has a patientive direct object, and this becomes the patientive subject in the intransitive). This phenomenon is called causative alternation. For example:
Passive voice is not an anticausative construction. In passive voice, the agent of causation is demoted from its position as a core argument (the subject), but it can optionally be re-introduced using an adjunct (in English, commonly, a "by"-phrase). In the examples above, "The window was broken", "The ship was sunk" would clearly indicate causation, though without making it explicit.
Romance languages.
In the Romance languages, many anticausative verbs are formed through a "pseudo-reflexive" construction, using a clitic pronoun (which is identical to the non-emphatic reflexive pronoun) applied on a transitive verb. For example (in Spanish, using the clitic "se"):
Another example in French:
Slavic languages.
In the Slavic languages, the use is essentially the same as in the Romance languages. For example (in Croatian, using "se"):
In East Slavic languages (such as Russian), the pronoun "se" becomes postfix "sya" (or "s"' after a vowel in Russian).
The suffix "sya" has a large number of uses and does not necessarily denote anticausativity (or even intransitivity). However, in most cases it denotes either passive voice or one of the subclasses of reflexivity (anticausativity, reciprocity, etc.)
There is a class of verbs (deponent verbs, "отложительные глаголы" "otlozhitel'nye glagoly") which "only" exist in this reflexive form (the suffix "sya" can't be removed). These are commonly anticausative or autocausative, and commonly refer to emotions, behavior, or factors outside one's control.
In addition, a verb may be put into an unaccusative/anticausative form by forming an impersonal sentence, with the verb typically either in its past tense neuter form, or in its present tense third person form:
Here as well there is a class of "impersonal verbs", which only exist in this impersonal form:
Afroasiatic languages.
In the Arabic language the form VII has the anticausative meaning. 
Urdu.
Urdu also abounds in such verbs. A very large number of antiaccusative verbs are used in it.
Japanese.
In Standard Japanese, productive morphology highly favors transitivization, in the sense that it has productive causitivization, but no anticausitivization. In the Hokkaido dialects and Northern Tōhoku dialect, however, the anticausative morpheme /rasar/ is employed with some verbs, such as "maku" 'to roll', "tsumu" 'to load', and "okuru" 'to send' as a means of producing an intransitive verb from a transitive verb.
Bardi.
Bardi is an Australian Aboriginal language in the Nyulnyulan family which uses the root "-jiidi-" 'go' to denote anticausatives as part of complex predicate constructions. For example, whereas one might causatively 'close' a door with the following construction:
a door might 'close' with the following construction
In the underived construction, the light verb "-ma-" "put" is used with a coverb (or preverb) "boonda" 'close'. In the anti-causative construction, the light verb reduces the valency of the predicate and the item which is closed becomes the subject. This is a regular alternation among complex predicates.