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. Linguistic typology is the typology that classifies languages by their features. ... For the topic in theoretical computer science, see Formal grammar Grammar is the study of rules governing the use of language. ... In grammar, an independent clause (or main clause) is a clause that can stand by itself as a grammatically viable simple sentence. ... According to a tradition that can be tracked back to Aristotle, every sentence can be divided in two main constituents, one being the subject of the sentence and the other being its predicate. ...

For example, in Italian:

Maria non vuole mangiare.

"Maria does not want to eat."

Non vuole mangiare.

[She] "Does not want to eat."

The subject "she" of the second sentence is only implied in Italian. English, on the other hand, requires an explicit subject in this sentence. The English language is a West Germanic language that originates in England. ...

Of the thousands of languages in the world, a considerable part are null subject languages, from a wide diversity of unrelated language families. They include Spanish, Hindi, Arabic, Chinese, and Japanese, as well as most languages related to these, and many others still. A language family is a group of languages related by descent from a common proto-language. ... Hindi (हिन्दी) is a language spoken mainly in North and Central India. ... Arabic ( or just ) is the largest living member of the Semitic language family in terms of speakers. ...

Characterization

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". Government and binding is a theory of syntax in the tradition of transformational grammar developed principally by Noam Chomsky in the 1980s. ... For other uses, see Syntax (disambiguation). ... In syntax, an empty category is a nominal element which does not have any phonological content and is therefore unpronounced; they may also be referred to as covert nouns, in contrast to overt nouns which are prounounced. ... In linguistics and grammar, a pronoun is a pro-form that substitutes for a noun or noun phrase with or without a determiner, such as you and they in English. ... In linguistics, anaphora is an instance of an expression referring to another. ...

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 pro-drop languages are null subject languages, not all null subject languages are pro-drop. A pro-drop language (from pronoun-dropping) is a language where pronouns can be deleted when they are in some sense pragmatically inferable (the precise conditions vary from language to language, and can be quite intricate). ... An object in grammar is a sentence element and part of the sentence predicate. ...

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. It has been suggested that Verbal agreement be merged into this article or section. ... Inflection of the Spanish lexeme for cat, with blue representing the masculine gender, pink representing the feminine gender, grey representing the form used for mixed-gender, and green representing the plural number. ... Grammatical person, in linguistics, is deictic reference to the participant role of a referent, such as the speaker, the addressee, and others. ... In linguistics, grammatical number is a morphological category characterized by the expression of quantity through inflection or agreement. ... In linguistics, grammatical gender is a morphological category associated with the expression of gender through inflection or agreement. ...

Examples

The following examples come from Portuguese:

• "I'm going home" can be translated either as Vou para casa or as Eu vou para casa, where eu means "I".
• "It's raining" can be translated as Está a chover, but not generally as *Ele está a chover, where ele would correspond to English it.
• "I'm going home. I'm going to watch TV" would only in exceptional circumstances be translated as ?Eu vou para casa. Eu vou ver televisão. At least the subject of the second sentence should be omitted, unless one wishes to express emphasis, as in "[I don't care what you are doing,] I am going home to watch TV."

As the examples illustrate, in many null subject languages, personal pronouns exist, and they can be used for emphasis, but are dropped whenever they can be inferred from the context. Some sentences do not allow a subject in any form, while in other cases an explicit subject without particular emphasis would sound awkward or unnatural. Personal pronouns are pronouns often used as substitutes for proper or common nouns. ... The word emphasis, in addition to its main dictionary meaning, may have the following techincal meanings. ...

Japanese and several other null subject languages are topic-prominent languages: they require an expressed topic in order for sentences to make sense. In Japanese, for instance, it is possible to start a sentence with a topic marked by the particle wa or ga. In subsequent sentences the topic can then be left unstated and understood to remain the same, until another one is explicitly introduced. For example, in the second sentence below, the subject ("we") is not expressed again but left implicit: A topic-prominent language is one that organizes its syntax so that sentences have a topic-comment (or theme-rheme) structure, where the topic is the thing being talked about (predicated) and the comment is what is said about the topic. ... In linguistics, the topic (or theme) is the part of the proposition that is being talked about (predicated). ...

Impersonal constructions

Main article: Impersonal verb

In some cases (impersonal constructions), a proposition has no referent at all. Pro-drop languages deal naturally with these, whereas many non-pro-drop languages such as English and French have to fill in the syntactic gap by inserting a dummy pronoun. "*Rains" is not a correct sentence; a dummy "it" has to be added: "It rains", French "Il pleut". In most Romance languages, however, "Rains" can be a sentence: Spanish "Llueve", Italian "Piove", Catalan "Plou", Portuguese "Chove", Romanian "Plouǎ", etc. An impersonal verb is a verb that cannot take a true subject, because it does not represent an action, occurrence, or state-of-being of any specific person, place, or thing. ... In general, a reference is something that refers or points to something else, or acts as a connection or a link between two things. ... A dummy pronoun (or more formally expletive pronoun or pleonastic pronoun) is a type of pronoun used in non-pro-drop languages, such as English, when a particular argument of a verb (or preposition) is nonexistent, unknown, irrelevant, already understood, or otherwise not to be spoken of directly, but a...

There are some languages that are not pro-drop but do not require this syntactic gap to be filled. For example, in Esperanto, "He made the cake" would translate as Li faris la kukon (never *Faris la kukon), but It rained yesterday would be Pluvis hieraŭ (not *Ĝi pluvis hieraŭ).   is the most widely spoken constructed international auxiliary language. ...

Null subjects in non-null subject languages

Other languages (sometimes called non-null subject languages) require each sentence to include a subject — this is the case for most Germanic languages, such as English and German, but also in French, a Romance language, and many others. In some cases, colloquial expressions, particularly in English, less so in German, and extremely rarely in French, allow for the omission of the subject in the same way that languages such as Spanish and Russian allow using "correct" grammar: This article does not cite any references or sources. ... The English language is a West Germanic language that originates in England. ... The Romance languages (sometimes referred to as Romanic languages) are a branch of the Indo-European language family, comprising all the languages that descend from Latin, the language of the Roman Empire. ...

"Bumped into George this morning." (I)

"Agreed to have a snifter to catch up on old times." (We)

"Told me what the two of you had been up to." (He)

"Went down to Brighton for the weekend?" (You)

The imperative form

Even in such non-null subject languages as English, it is standard for clauses in the imperative mood to lack explicit subjects; for example: In linguistics, many grammars have the concept of grammatical mood, which describes the relationship of a verb with reality and intent. ...

"Take a break; you're working too hard."

"Shut up!"

An explicit declaration of the pronoun in English in the imperative mood is possible, usually for emphasis but not necessary:

"Don't you listen to him!"

French and German offer less flexibility with regards to null subjects. In French, it is neither grammatically correct nor possible to include the subject within the imperative form (the vous in the expression taisez-vous would stem from the fact that se taire, to be silent is a reflexive verb and is thus the object).

In German, the informal form du may be added to the imperative in a colloquial manner for emphasis (Mach du das, you do it). The formal imperative requires the addition of the subject Sie (as in Machen Sie das) as the formal imperative form of a verb is identical to the infinitive (which also can be used as a "neutral" imperative).

Auxiliary languages

Interlingua

Interlingua, while officially a non-null subject language, sometimes allows for the omission of pronouns. This is most common with the pronoun "il", which means "it" when referring to part of a sentence or to nothing in particular. Examples of this word include Interlingua is an international auxiliary language (IAL) published in 1951 by the International Auxiliary Language Association (IALA). ... This article is an informal outline of the grammar of Interlingua, an international auxiliary language first publicized by IALA. It follows the usage of the original grammar text (Gode & Blair, 1951), which is accepted today but regarded as conservative. ...

Il pluvia.

It's raining.

Il es ver que ille arriva deman.

It is that he arrives tomorrow.

"Il" tends to be omitted whenever the contraction "it's" can be used in English. Thus, "il" may be omitted from the second sentence above: "Es ver que ille arriva deman".

In practice, subject pronouns are sometimes omitted when they can be inferred from a previous sentence:

Illa audiva un crito. Curreva al porto. Aperiva lo.

She heard a cry. Ran to the door. Opened it.

The second-person pronoun is usually omitted from imperative clauses:

Cessa lo! Stoppa lo!

Stop it! Stop it!

This pronoun can be re-inserted for emphasis:

Tu cessa lo! Tu stoppa lo!

You stop it! You stop it!

Esperanto

Esperanto, while not officially pro-drop, sometimes exhibits pronoun deletion in casual use. This deletion is normally limited to subject pronouns, especially where that pronoun has been used just previously (as either a subject or object).   is the most widely spoken constructed international auxiliary language. ...

Ĉu vi vidas lin? Venas nun.

QUESTION-PARTICLE you see him? Comes now.

Do you see him? He is coming now.

In this case, "lin" meant "him" as an object pronoun. The omission of the subject-pronoun equivalent "li" in the subsequent sentence is grammatically logical, since it is more likely that he comes than it is that you come.

Occasionally, even more pronoun-shaving occurs.

Ĉu vidas lin? Venas nun.

QUESTION-PARTICLE see him? Comes now.

Do you see him? He is coming now.

The omission of "vi" ("you") from the question can be perceived as logical, especially if the question was asked in a context where only one other person (or group of people) was present.

See also

• Agreement (linguistics)
• Anaphora (linguistics)
• Impersonal verb
• Pro-drop language

In languages, agreement is a form of cross-reference between different parts of a sentence or phrase. ... In linguistics, anaphora is an instance of an expression referring to another. ... An impersonal verb is a verb that cannot take a true subject, because it does not represent an action, occurrence, or state-of-being of any specific person, place, or thing. ... A pro-drop language (from pronoun-dropping) is a language where pronouns can be deleted when they are in some sense pragmatically inferable (the precise conditions vary from language to language, and can be quite intricate). ...

References

• Chomsky, N. (1981). Lectures on Government and Binding: The Pisa Lectures. Holland: Foris Publications, Reprint. 7th Edition. Berlin and New York: Mouton de Gruyter, 1993.