T-V pronouns
Definition - Second person pronouns that are used to indicated different levels of formality.

1. The informal pronoun is called the T-pronoun or T-form (e.g. the French tu and the German du).
2. The formal pronoun is called the V-pronoun or V-form (e.g. vous in French and Sie in German).

Etymology -
The expressions T-form and V-form were introduced in 1960 by R. Brown and A. Gilman in The Pronouns of Power and Solidarity in American Anthropologist [4 (6): 24–39]. The T and V refer to the initial letters of the Latin pronouns tu and vos.

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