Clusivity
In linguistics, clusivity is a grammatical distinction between "inclusive" and "exclusive" first-person pronouns and verbal morphology, also called "inclusive "we"" and "exclusive "we"". Inclusive "we" specifically includes the addressee (that is, one of the words for "we" means "you and I and possibly others"), while exclusive "we" specifically excludes the addressee (that is, another word for "we" means "he/she/they and I, but not you"), regardless of who else may be involved. While imagining that this sort of distinction could be made in other persons (particularly the second) is straightforward, in fact the existence of second-person  clusivity (you vs. you and them) in natural languages is controversial and not well attested. While clusivity is not a feature of standard English language, it is found in many languages around the world. The first published description of the inclusive-exclusive distinction by a European linguist was in a description of languages of Peru in 1560 by Domingo de Santo Tomás in his "Grammatica o arte de la lengua general de los indios de los Reynos del Perú", published in Valladolid, Spain. Schematic paradigm. Clusivity paradigms may be summarized as a two-by-two grid: Morphology. In some languages , the three first-person pronouns appear to be unrelated. This is the case for Chechen, which has singular "so/со," exclusive "txo/тхо," and inclusive "vay/вай." In others, all three are related, as in Tok Pisin (an English creole spoken in Papua New Guinea) singular "mi," exclusive "mi-pela," and inclusive "yu-mi" (a compound of "mi" with "yu" "you") or "yu-mi-pela." However, when only one of the plural pronouns is related to the singular, it may be either one. In some dialects of Mandarin Chinese, for example, inclusive or exclusive 我們／我们 "wǒmen" is the plural form  of singular "wǒ" "I", while inclusive 咱們／咱们 "zánmen" is a separate root. However, in Hadza it is the inclusive, "’one-be’e," which is the plural of the singular "’ono" ("’one-") "I", while the exclusive "’oo-be’e" is a separate root. It is not uncommon for two separate words for "I" to pluralize into derived forms having a clusivity distinction. For example, in Vietnamese the familiar word for "I" ("ta") pluralizes to inclusive we ("chúng ta") and the formal or cold word for "I" ("tôi") pluralizes into exclusive we ("chúng tôi"). In Samoan, the singular form of the exclusive pronoun is  the regular word for "I", while the singular form of the inclusive pronoun may also occur on its own, in which case it also means "I", but with a connotation of appealing or asking for indulgence. In the Kunama language of Eritrea, the first person inclusive and exclusive distinction is marked on dual and plural forms of verbs, independent pronouns, and possessive pronouns. Distinction in verbs. Where verbs are inflected for person, as in the native languages of Australia and many Native American languages, the inclusive-exclusive distinction can be made there as well. For example, in Passamaquoddy "I/we  have it" is expressed In Tamil on the other hand, the two different pronouns have the same agreement on the verb. First-person clusivity. First-person clusivity is a common feature among Dravidian, Kartvelian, and Caucasian languages, Australian and Austronesian languages, and is also found in languages of eastern, southern, and southwestern Asia, Americas, and in some creole languages. Some African languages also make this distinction, such as the Fula language. No European language outside the Caucasus makes this distinction grammatically, but some constructions may be semantically inclusive or exclusive. Singular inclusive forms. Several Polynesian languages, such as Samoan and  Tongan, have clusivity with overt dual and plural suffixes in their pronouns. The lack of a suffix indicates the singular. The exclusive form is used in the singular as the normal word for "I", but the inclusive also occurs in the singular. The distinction is one of discourse: the singular inclusive has been described as the "modesty I" in Tongan, often rendered in English as "one", while in Samoan its use has been described as indicating emotional involvement on the part of the speaker. Second-person clusivity. In theory, clusivity of the second person should be a possible distinction, but  its existence is controversial. Some notable linguists, such as Bernard Comrie, have attested that the distinction is extant in spoken natural languages, while others, such as John Henderson, maintain that the human brain does not have the capacity to make a clusivity distinction in the second person. Many other linguists take the more neutral position that it could exist but is nonetheless not currently attested. Clusivity in the second person is conceptually simple but nonetheless if it exists is extremely rare, unlike clusivity in the first. Hypothetical second-person clusivity would be the distinction between "you and you (and you  and you ... all present)" and "you and someone else whom I am not addressing currently." These are often referred to in the literature as "2+2" and "2+3", respectively (the numbers referring to second and third person as appropriate). Horst J. Simon provides a deep analysis of second-person clusivity in his 2005 article. He concludes that oft-repeated rumors regarding the existence of second-person clusivity—or indeed, any [+3] pronoun feature beyond simple exclusive we – are ill-founded, and based on erroneous analysis of the data. Distribution of the clusivity distinction. The inclusive–exclusive distinction  occurs nearly universally among the Austronesian languages and the languages of northern Australia, but rarely in the nearby Papuan languages. (Tok Pisin, an English-Melanesian pidgin, generally has the inclusive–exclusive distinction, but this varies with the speaker's language background.) It is widespread in India, featuring in the Dravidian and Munda languages, as well as in several Indo-European languages of India such as Oriya, Marathi, Rajasthani, Punjabi, Sindhi, and Gujarati (which either borrowed it from Dravidian or was retained as a substratum if Dravidian was displaced). It can also be found in the languages of eastern Siberia, such  as Tungusic, from which it was borrowed into northern Mandarin Chinese. In indigenous languages of the Americas it is found in about half the languages, with no clear geographic or genealogical pattern. It is also found in a few languages of the Caucasus and Sub-Saharan Africa, such as Fulani and Khoekhoe. It is, of course, possible in any language to express the idea of clusivity semantically, and many languages provide common forms that clarify the ambiguity of their first person pronoun (English "the rest of us", Italian "noialtri"). A language with a true clusivity distinction, however, does not provide  a first person plural with "indefinite" clusivity: where the clusivity of the pronoun is ambiguous; rather, the speaker is forced to specify – by choice of pronoun or inflection – whether they are including the addressee or not. This rules out most European languages, for example. Clusivity is nonetheless a very common language feature overall. Some languages with more than one plural number make the clusivity distinction only in, for example, the dual, but not in the greater plural. Others make it in all numbers. In the table below, the plural forms are the ones preferentially listed.