An anticausative verb 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" means "being accelerated down by gravity" or "being dropped/pushed down by someone"? Is "old age" a causation agent for "dying"?).
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:
- He broke the window. → The window broke.
- Some pirates sank the ship. → The ship sank.
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.
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):
- El vidrio se quebró. "The glass shattered."
- Se está hundiendo el barco. "The boat is sinking."
Another example in French:
- Les poissons se pêchaient et se vendaient. "Fish were being fished and sold."
- Staklo se razbilo. "The glass shattered."
In the Arabic language the form VII has the anticausative meaning.
- "yanqalibu" means "he himself changes" (the cause of his change is not known).
Urdu also abounds in such verbs. A very large number of antiaccusative verbs are used in it.
- "khānā puk rahā he" "کھانا پک رہا ہے" "The food is cooking."
- "pānī ubal rahā he" "پانی ابل رہا ہے" "The water is boiling."
- Changing valency: Case studies in transitivity (edited by R. M. W. Dixon & A. Y. Aikhenvald, Research Centre for Linguistic Typology, Le Trobe University, Melbourne)