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. (November 2012)
In 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.
Typically, null-subject languages express person, number, and/or gender agreement with the referent on the verb, rendering a subject noun phrase redundant. 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.
For example, in Italian the subject "she" can be either explicit or implicit:
- Maria non vuole mangiare. lit. Maria not wants [to-]eat, "Maria does not want to eat".
- Non vuole mangiare. lit. Subject not wants [to-]eat, "[(S)he] does not want to eat."
The subject "(s)he" of the second sentence is only implied in Italian. English and French, on the other hand, require an explicit subject in this sentence.
Of the thousands of languages in the world, a considerable number are null-subject languages, from a wide diversity of unrelated language families. They include Albanian, Arabic, Basque, Berber, Bengali, Catalan, Chinese, Estonian, Finnish, Galician, Gujarati, Greek, Hebrew, Hindi, Hungarian, Italian, Romanian, Japanese, Korean, Persian, Portuguese, Punjabi, Sindhi, Slavic languages, Spanish, Tamil and the Turkic languages, as well as most languages related to these, and many others still. In fact, it is rather the absence of pronoun dropping that is an areal feature of Standard Average European, including French, German, and English.
In the framework of government and binding theory of syntax, the term null subject refers to an empty category. The empty category in question is thought to behave like an ordinary pronoun with respect to anaphoric reference and other grammatical behavior. Hence it is most commonly referred to as "pro".
This phenomenon is similar, but not identical, to that of pro-drop languages, which may omit pronouns, including subject pronouns, but also object pronouns. While all pro-drop languages are null-subject languages, not all null-subject languages are pro-drop.
In null-subject languages that have verb inflection in which the verb inflects for person, the grammatical person of the subject is reflected by the inflection of the verb and likewise for number and gender.