Depassivization

Depassivization is a linguistic process where a passive construction is transformed into an active one. This typically involves changing the grammatical structure of a sentence so that the subject of the active sentence is the object of the passive sentence, and the verb is changed from passive voice to active voice. For example, the passive sentence "The ball was hit by the boy" can be depassivized into the active sentence "The boy hit the ball."

This transformation is common in language acquisition and is also a feature of some natural language processing tasks, such as machine translation and text summarization. In machine translation, depassivization can help to produce more natural-sounding target language sentences. In text summarization, it can be used to condense information by removing the agent of a passive verb if it is not essential.

The process of depassivization often requires identifying the agent of the passive verb, which is usually introduced by the preposition "by" in English. Once the agent is identified, it becomes the subject of the active sentence, and the verb is conjugated in the active voice. The object of the active sentence is typically the subject of the original passive sentence.

While depassivization is straightforward in many cases, there can be complexities. For instance, if the agent is omitted in the passive sentence (e.g., "The window was broken"), depassivization might require inferring a plausible agent or leaving the agent unspecified in the active version. The specific rules and ease of depassivization can vary between languages.