Ergative verb

In linguistics, an ergative verb is a verb that can be either transitive or intransitive, and whose subject when intransitive corresponds to its direct object when transitive.

In English, most verbs can be used intransitively, but ordinarily this does not change the role of the subject; consider, for example, "He ate the soup" (transitive) and "He ate" (intransitive), where the only difference is that the latter does not specify what was eaten. By contrast, with an ergative verb the role of the subject changes; consider "it broke the window" (transitive) and "the window broke" (intransitive).

Ergative verbs can be divided into several categories:

Some of these can be used intransitively in either sense: "I'm cooking the pasta" is fairly synonymous with both "The pasta is cooking" (as an ergative verb) and "I'm cooking", although it obviously gives more information than either.

Unlike a passive verb, a nominalization, an infinitive, or a gerund, which would allow the agent to be deleted but would also allow it to be included, the intransitive version of an ergative verb normally requires the agent to be deleted:

Indeed, the intransitive form of an ergative verb can be used to suggest that there is no agent. With some non-ergative verbs, this can also be achieved using the reflexive voice:

This use of the reflexive voice can be used to indicate the lack of any agent, but it can also be used in cases when a specific agent is unknown. For example, the phrases "John broke the window, or maybe Jack did — at any rate, the window broke" and "John solved the problem, or maybe Jack did — at any rate, the problem was solved" both have quite naturally understandable meanings, though they're slightly idiomatic.

Another way to construct the reflexive voice is:

This use of the reflexive voice indicates that the subject of the sentence is the causative agent; the phrase "John solved the problem, or maybe Jack did — at any rate, the problem solved itself" is literally self-contradictory, though idiomatic usage does not always follow this prescription. Accordingly, some grammarians would consider both "The window broke" and "The problem solved itself" to be examples of a distinct voice, the middle voice.

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