Pro-drop language

A pro-drop language (from "pronoun-dropping") is a language in which certain classes of pronouns may be omitted when they are pragmatically or grammatically inferable (the precise conditions vary from language to language, and can be quite intricate). The phenomenon of "pronoun-dropping" is also commonly referred to as zero or null anaphora. In the case of pro-drop languages, null anaphora refers to the fact that that the null position does have referential properties, meaning it is not a null dummy pronoun. Pro-drop is only licensed in languages that have a positive setting of the pro-drop parameter, which allows the null element to be identified by its governor. In pro-drop languages with highly inflected verbal morphology, the expression of the subject pronoun is considered unnecessary because the verbal inflection indicates the person and number of the subject, thus the referent of the null subject can be inferred from the grammatical inflection on the verb.

Even though in everyday speech there are instances when who or what is being referred to can be inferred from context, non-pro-drop languages still require the pronoun. However, pro-drop languages allow those referential pronouns to be omitted, or be phonologically null. Among major languages, two of which might be called a pro-drop language are Japanese and Korean (featuring pronoun deletion not only for subjects, but for practically all grammatical contexts). Chinese, Slavic languages, and American Sign Language also exhibit frequent pro-drop features. Non-pro-drop is rather an areal feature of Standard Average European including French, German, and English.

Some languages might be considered only partially pro-drop in that they allow deletion of the subject pronoun. These null subject languages include most Romance languages (French is an exception) as well as all the Balto-Slavic languages and to a limited extent Icelandic.

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