Although not widely accepted in linguistics, the term preverb is used in Caucasian (including all three families: Northwest Caucasian, Northeast Caucasian and Kartvelian), Caddoan, Athabaskan, and Algonquian linguistics to describe certain elements prefixed to verbs. In the context of Indo-European languages, the term is usually used for separable verb prefixes. Theoretically, any prefix could be called a preverbal element. However, in practice, the term preverb applies more narrowly in those families and refers to a prefixed element that is normally outside the premise of verbal morphology like locations of noun elements or, less often, noun elements themselves. Northwest Caucasian languages In Northwest Caucasian languages, they can have nouns, directional and locative preverbs (like prepositions), like in this example from Ubykh: Caddoan In Caddoan linguistics, preverbal elements are less well defined as a class, and often, "preverb" designates a part of the verbal root that can be separated from the rest of the root by certain prefixes, as in this Wichita example: Mandarin Chinese For Mandarin Chinese and many other varieties of Chinese, the term refers to some words that carry the meanings of prepositions in English. In Chinese, they are lexically verbs and appear before the noun in question. They are more commonly referred to as coverbs. Georgian In Georgian, a Kartvelian language, the main function of a preverb is to distinguish the present tenses and the future tenses. To turn a present tense verb into a future tense, a preverb is added to the verb compound. In addition, preverbs also have directional meanings in Georgian. Preverbs are directly attached to the beginning of the verb compound: აკეთებს ak'etebs ("he does it") and გააკეთებს gaak'etebs ("he will do it") ვწერ vts'er ("I am writing") and დავწერ davts'er ("I will write") Note in those two examples that the meaning of the future tense is achieved only by adding the preverb; no other grammatical change occurs. In these examples, preverbs have directional meanings: მოდის modis ("he/she is coming") მიდის midis ("he/she is going") ადის adis ("he/she is going up (the stairs)", "he/she is getting on (a bus)") ჩამოდის chamodis ("he/she is arriving") შემოდის shemodis ("he/she is entering") Again, note that only the preverbs are changed to convey the meaning of various directional meanings. Preverbs add directional meanings not only to the verbs of motion but also to any other kind of verbs. Compare the examples of the verb -tser- ("write"): დავწერე davts'ere