Subject (grammar)

The subject of a verb is the argument which generally refers to the origin of the action or the undergoer of the state shown by the verb. However, this definition depends on the particular language under consideration. In languages where a passive voice exists, the subject of a passive verb may be the target or result of the action. This is a semantic definition.

An alternative definition would be: the subject of an intransitive verb is its only argument; the subject of a transitive verb is its main argument. Transitive verbs usually agree with the subject, if such agreement exists at all. This is a morphosyntactic definition.

The subject most often carries the least-marked case; that is, in a language that marks morphological case on the arguments of a proposition, the subject tends to be marked with the least salient morphology, or is left unmarked.

In addition, the subject tends to come first of the two core arguments of a transitive verb; only a minority of languages place the subject after the object.

Finally, the subject tends to be the topic of the proposition. In languages with no other means to mark a topic, making an object into a subject by using passivization (I did it → it was done) is a way to topicalize said object. (See also topic-prominent languages.)

There are languages where a verb is allowed to have no arguments, and therefore no subject. These cases must be distinguished from those where the subject can be dropped (and left implicit, referenced by agreement in the verb, or simply to be guessed from context). In English, a verb must always have a subject, either a noun or noun phrase, or a pronoun. Even verbs like rain must carry a dummy "subject" shown by the pronoun it.