Politeness is social deixis that expresses a low degree of solidarity between the speaker and the addressee.
Some uses of the second person pronouns Sie in German and vous in French signal politeness.
Hartmann, R.R.K., and F.C. Stork. 1972.Dictionary of language and linguistics. London: Applied Science.
Brown, Roger, and Albert Gilman. 1960. "The pronouns of power and solidarity." In Sebeok 1960