A 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. Put simply, some languages (see below) allow omitting the subject of a sentence. 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.
Pro-drop is a problem when translating to a non-pro-drop language such as English, which requires the pronoun to be added, especially noticeable in machine translation. It can also contribute to transfer errors in language learning.
An areal feature of some European languages is that pronoun dropping is not, or seldom, possible (see Standard Average European); this is the case for English, French, German,Martin Haspelmath, The European linguistic area: Standard Average European, in Martin Haspelmath, et al., Language Typology and Language Universals, vol. 2, 2001, pp. 1492-1510 and Emilian, among others.Fabio Foresti, Dialetti emiliano-romagnoli, Enciclopedia Treccani In contrast, Japanese, Mandarin Chinese, Vietnamese, Slavic languages, Summary. Uralic languages, Assyrian Neo-Aramaic, Kra-Dai languages, Italian, Spanish, and Portuguese exhibit frequent pro-drop features. Some languages, such as Greek and Hindi also exhibit pro-drop in any argument.
Usage of term
In Noam Chomsky's "Lectures on Government and Binding", the term is used for a cluster of properties of which "null subject" was one (for the occurrence of pro as a predicate rather than a subject in sentences with the copula see Moro 1997).
Thus, a one-way correlation was suggested between inflectional agreement (AGR) and empty pronouns on the one hand and between no agreement and overt pronouns, on the other. In the classical version, languages which not only lack agreement morphology but also allow extensive dropping of pronouns—such as Japanese, Chinese, Korean, and Vietnamese—are not included, as is made clear in a footnote: "The principle suggested is fairly general, but does not apply to such languages as Japanese in which pronouns can be missing much more freely." (Chomsky 1981:284, fn 47).
The term pro-drop is also used in other frameworks in generative grammar, such as in lexical functional grammar (LFG), but in a more general sense: "Pro-drop is a widespread linguistic phenomenon in which, under certain conditions, a structural NP may be unexpressed, giving rise to a pronominal interpretation." (Bresnan 1982:384).
The empty category assumed (under government and binding theory) to be present in the vacant subject position left by pro-dropping is known as pro, or as "little pro" (to distinguish it from "big PRO", an empty category associated with non-finite verb phrases).R.L. Trask, A Dictionary of Grammatical Terms in Linguistics, Routledge 2013, p. 218.
Cross-linguistic variation It has been observed that pro-drop languages are those with either rich inflection for person and number (Persian, Polish, Czech, Portuguese, etc.) or no such inflection at all (Japanese, Chinese, Korean, etc.), but languages that are intermediate (English, French) are non-pro-drop.
While the mechanism by which overt pronouns are more "useful" in English than in Japanese is obscure, and there are exceptions to this observation, it still seems to have considerable descriptive validity. As Huang puts it, "Pro-drop is licensed to occur either where a language has full agreement, or where a language has no agreement, but not where a language has impoverished partial agreement."Huang, C.-T. James. "On the distribution and reference of empty pronouns". Linguistic Inquiry 15: 531-574. 1984.
In pro-drop languages with a 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.
Barbosa defines these typological patterns as null-subject languages (NSL), expressing that the term itself, pro-drop, can be subcategorized into categories such as: topic (discourse) pro-drop, partial NSL (partial pro-drop) and consistent NSL (full pro-drop).
Topic pro-drop languages In everyday speech there are instances when who or what is being referred to — namely, the topic of the sentence — can be inferred from context. Languages which permit the pronoun to be inferred from contextual information are called topic-drop (also known as discourse pro-drop) languages: thus, topic pro-drop languages allow referential pronouns to be omitted, or be phonologically null. (In contrast, languages that lack topic pro-drop as a mechanism would still require the pronoun.) These dropped pronouns can be inferred from previous discourse, from the context of the conversation, or generally shared knowledge. Among major languages, some which might be called topic pro-drop languages are Japanese, Korean, and Mandarin. Topic prominent languages like Korean, Mandarin and Japanese have structures which focus more on topics and comments as opposed to English, a subject-prominent language.Li, Charles & Thompson, Sandra. (1976). Subject and Topic: A New Typology of Language. Subject and Topic. It is this topic-first nature that enables the inference of omitted pronouns from discourse.
Korean The following example from Jung (2004:719) Korean shows the omission of both pronouns in the subject and object position.
Japanese
Consider the following examples from Japanese:
The words in parentheses and boldface 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 sound unnatural. Learners of Japanese as a second language, especially those whose first language is non-pro-drop like English or French, often supply personal pronouns where they are pragmatically inferable, an example of language transfer.
Mandarin
The above-mentioned examples from Japanese are readily rendered into Mandarin:
Unlike in Japanese, the inclusion of the dropped pronouns does not make the sentence sound unnatural.
Vietnamese Vietnamese can naturally omit subjects, especially in universally casual clauses, proverbs and idioms:
Partial pro-drop languages
Languages with partial pro-drop have both agreement and referential null subjects that are restricted with respect to their distribution. The partial null-subject languages include most Balto-Slavic languages, which allow for the deletion of the subject pronoun. Hungarian allows deletion of both the subject and object pronouns.
Slavic languages The following table provides examples of subject pro-drop in Slavic languages. In each of these examples, the 3rd person masculine singular pronoun 'he' in the second sentence is inferred from context. +Subject pro-drop in Slavic languagesLanguage'(I) see [him].''(He) is coming.'Belarusian Bulgarian CzechMacedonian PolishRussian Serbo-Croatian SloveneUkrainian In the East Slavic languages, even the objective pronoun can be omitted in the present and future tenses (both imperfect and perfective). In these languages, the missing pronoun is not inferred strictly from pragmatics, but partially indicated by the morphology of the verb (Russian , Bulgarian , Polish , Czech , etc.). However, the past tense of both imperfective and perfective in the modern East Slavic languages inflects by gender and number but not person because the present tense conjugations of the copula "to be" (Russian , Ukrainian , Belarusian ) have practically fallen out of use. As such, the pronoun is often included in these tenses, especially in writing.
Uralic languages In Finnish, the verb inflection replaces first- and second-person pronouns (but not thirds, which remain obligatory) in simple sentences: 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 possessive pronouns but possessive suffixes, e.g. -ni as in kissani "my cat", are also used, as in Kissani söi kalan ("my cat ate a fish"). A peculiarity of Colloquial Finnish is that the pronoun me ("we") can be dropped if the verb is placed in the passive voice (e.g. haetaan, Standard "it is fetched", colloquial "we fetch"). Estonian, a close relative of Finnish, has a tendency that is less clear. Literary Estonian generally uses explicit personal pronouns in the literary language, but they are often omitted in colloquial Estonian.
Hungarian is also pro-drop, and subject pronouns are used only for emphasis: (Én) mentem "I went". Because of the definite conjugation, object pronouns can be often elided as well. For example, the question (Ti) látjátok a macskát? "Do (you pl.) see the cat?" can be answered with just látjuk "(We) see (it)" because the definite conjugation renders the object pronoun superfluous.
Hebrew Modern Hebrew, like Biblical Hebrew, is a "moderately" pro-drop language. In general, subject pronouns must be included in the present tense. Since Hebrew has no verb forms expressing the present tense, the present tense is formed by using the present participle (somewhat like English I am guarding). The Hebrew participle, as is the case with other adjectives, declines only in grammatical gender and number (like the past tense in Russian), thus:
I (m.) guard (ani shomer) =
You (m.) guard (ata shomer) =
He guards (hu shomer) =
I (f.) guard (ani shomeret) =
We (m.) guard (anachnu shomrim) =
Since the forms that are used for the present tense lack the distinction between grammatical persons, explicit pronouns must be added in most cases.
In contrast, the past tense and the future tense the verb form is inflected for person, number, and gender. Therefore, the verb form itself indicates sufficient information about the subject. The subject pronoun is therefore normally dropped, except in third-person.
I (m./f.) guarded (shamarti) =
You (m. pl.) guarded (sh'martem) =
I (m./f.) will guard (eshmor) =
You (pl./m.) will guard (tishm'ru) =
Many nouns can take suffixes to reflect the possessor in which case the personal pronoun is dropped. In daily usage, the inflection of Modern Hebrew nouns is common only for some nouns. In most cases, inflected possessive pronouns are used. In Hebrew, possessive pronouns are treated mostly like adjectives and follow the nouns which they modify. In Biblical Hebrew, inflection of more sophisticated nouns is more common than in modern usage.
Full pro-drop languages Full pro-drop languages, also known as consistent NSLs, are languages that are characterized by rich subject agreement morphology where subjects are freely dropped under the appropriate discourse conditions. In some contexts, pro-drop in these languages is mandatory and also occurs in contexts in which pro-drop cannot happen for partial pro-drop languages. The following languages exhibit full pro-drop in their own distinct ways.
Hindi South Asian languages such as Hindi, in general, have the ability to pro-drop any and all arguments. Hindi is a split-ergative language and when the subject of the sentence is in the ergative case (also when the sentence involves the infinitive participle, which requires the subject to be in the dative caseBhatt, Rajesh (2003). Experiencer subjects. Handout from MIT course “Structure of the Modern Indo-Aryan Languages”.), the verb of the sentence agrees in gender and number with the object of the sentence, hence making it possible to drop the object since it can be contextually inferred from the gender of the verb.