Voice (grammar)In grammar, the voice (aka diathesis) of a verb describes the relationship between the action (or state) that the verb expresses and the participants identified by its arguments (subject, object, etc.). When the subject is the agent or doer of the action, the verb is in the active voice. When the subject is the patient, target or undergoer of the action, the verb is said to be in the passive voice. When the subject both performs and receives the action expressed by the verb, the verb is in the middle voice.
Valency (linguistics)In linguistics, valency or valence is the number and type of arguments controlled by a predicate, content verbs being typical predicates. Valency is related, though not identical, to subcategorization and transitivity, which count only object arguments – valency counts all arguments, including the subject. The linguistic meaning of valency derives from the definition of valency in chemistry. Like valency found in chemistry, there is the binding of specific elements.
Intransitive verbIn grammar, an intransitive verb is a verb whose context does not entail a direct object. That lack of transitivity distinguishes intransitive verbs from transitive verbs, which entail one or more objects. Additionally, intransitive verbs are typically considered within a class apart from modal verbs and defective verbs. In the following sentences, verbs are used without a direct object: "Rivers flow." "I sneezed." "My dog ran." "Water evaporates when it's hot." "You've grown since I last saw you!" "I wonder how old I will be when I die.
Null-subject languageIn linguistic typology, a null-subject language is a language whose grammar permits an independent clause to lack an explicit subject; such a clause is then said to have a null subject. In the principles and parameters framework, the null subject is controlled by the pro-drop parameter, which is either on or off for a particular language. Typically, null-subject languages express person, number, and/or gender agreement with the referent on the verb, rendering a subject noun phrase redundant.
Pro-drop languageA pro-drop language (from "pronoun-dropping") is a language in which certain classes of pronouns may be omitted when they can be pragmatically or grammatically inferable. The precise conditions vary from language to language, and can be quite intricate. The phenomenon of "pronoun-dropping" is part of the larger topic of zero or null anaphora. The connection between pro-drop languages and null anaphora relates to the fact that a dropped pronoun has referential properties, and so is crucially not a null dummy pronoun.
