Unaccusative verb

Unaccusative verbs are a subclass of intransitives. Their single arguments denote direct objects in relational grammar and GB, instead of agent-like participants. Thus unaccusatives are defined syntactically rather than semantically as verbs that assign no external theta-role and no structural Case.

Its argument is in object position at D-structure, but has to move to subject position in order to receive (nominative) Case (from INFL). The syntactic behaviour of unaccusatives differs in various ways from non-unaccusative intransitive verbs ( unergative verbs). In languages that have a distinction between the perfective auxiliaries 'to be' and 'to have', the unaccusatives take 'to be', while the unergatives take 'to have'.

Examples
English unaccusatives are fall, arrive or melt. In German there are unaccusative verbs like entgleiten (slip) or zerbrechen (break).

Example
the Italian sentences in (i) and the Dutch sentences in (ii) are examples.

(i)   a  ha telefonato Gianni has telephoned G       b  Ã¨ arrivato Claudio is arrived C (ii)  a Jan heeft getelefoneerd J has telephoned b Klaas is gearriveerd K has arrived

Furthermore, unaccusatives cannot be passivized, as opposed to unergatives (in languages with impersonal passives). This is shown by the contrast between the Dutch (iii) and (iv).

(iii)	er wordt door Jan getelefoneerd there is by J telephoned (iv)  *er wordt door Klaas gearriveerd there is by K arrived

In Italian, a further diagnostic to distinguish unaccusatives from unergatives is the possibility of ne-cliticization.

Comments
In English as well as in German, unaccusatives differ from other verbs in the selection of their perfective auxiliary. The unaccusatives take a form of to be or sein, respectively, whereas the other verbs take a form of to have or haben, respectively.

Synonyms

 * Ergative verb
 * Inactive verb
 * Stative verb

Antonyms

 * Accusative verb
 * Unergative verb
 * Active verb
 * Agentive verb

Origin
The name "unaccusative" denotes that the single argument of the intransitive verb does not behave like the subject of a transitive verb, which would be expected in an accusative alignment. It was introduced by Perlmutter (1978), but originally coined by G. Pullum (cf. Pullum 1988).

Other languages
German unakkusativisches Verb