Pro-drop language

Pro-drop language (from "pronoun-dropping") is a language where pronouns can be elided (deleted) when considered unnecessary or redundant by the speaker.

In everyday speech there are often instances when it is obvious who or what is being referred to, or it can be guessed from context. In a pro-drop language, the pronouns that would normally take the place of those referents can be elided once the context has been established. Among major languages, the prototype of pro-drop languages is probably Japanese (featuring pronoun elision not only for subjects, as is often implied, but for practically all grammatical contexts), but Romance languages such as Portuguese, Spanish, Italian and Romanian are also pro-drop.

Examples

Consider the following examples from Japanese:

Kono kēki wa oishii. Dare ga tsukutta no?

this cake TOPIC tasty. who SUBJECT make-PAST?

"This cake is tasty. Who made it?"

Shiranai. Ki ni itta?

know-NEGATIVE. like-PAST?

"I don't know. Do you like it?"

The pronouns in bold in the English translations ("it" in the first line, "I", "you", and "it" in the second) appear nowhere in the Japanese sentences, but are understood from context. If nouns or pronouns were supplied, the resulting sentences would be grammatically correct but not natural. (Learners of Japanese as a second language, especially those whose first language is non-pro-drop like English, often make the mistake of supplying personal pronouns where pragmatically inferrable.)

Generalizations across languages

Portuguese, Spanish, Italian and Romanian can elide subject pronouns only, and they often do even when the referent has not been mentioned, but this is helped by the fact that verbs in these three languages have a person/number inflection. It has been observed that pro-drop languages are those with either rich inflection for person and number (Portuguese, etc.) or no inflection (Japanese, Chinese, etc.), while languages that are intermediate (English, standard French, etc.) are non-pro-drop. While the mechanism by which overt pronouns are more "useful" in English than Japanese is obscure, and while there are exceptions to this observation, it still seems to have some descriptive validity.

English

English is considered a non-pro-drop language. Nonetheless, subject pronouns are almost always dropped in commands (e.g., Come here); and in informal speech, pronouns and other words may sometimes be dropped, especially from the beginnings of sentences:

• [Have] you ever been there? or [Have you] ever been there?
• I'm going to the store. [Do] you want to come with [me]?
• Seen on signs: [I am/We are] out to lunch; [I/we will be] back at 1:00 P.M.
• What do you think of it? – I like [it]!

Note that these elisions are generally restricted to very informal speech and certain fixed expressions, and the rules for their use are complex and vary between dialects.

Finno-Ugric languages

In Finno-Ugric languages such as Finnish, the verb inflection replaces first and second person pronouns in simple sentences, e.g. menen "I go", menette "all of you go". Pronouns are typically left in place only when they need to be inflected, e.g. me "we", meiltä "from us". There are no possessive pronouns, but possessive suffixes, e.g. -ni as in kissani "my cat".

Impersonal constructions

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. For example, just "Rains" is not a correct sentence, but a dummy "it" has to be added: It rains.

There are some languages that are not pro-drop but do not expect 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 hieraux" (not "Gxi pluvis hieraux").