From around 1300, aT–V distinction emerged in Middle English where formalye was used to address one's superiors, elders or others to whom one might wish to show politeness or respect, while informalþou was used to address inferiors and younger generations.
When both speakers were of approximately equal status, the rules regarding the use of informalþou and formalye were relatively fluid: speakers could indiscriminately alternate between them or employ them to provide subtle emotional cues, such as "moments of emotional intensity or intimacy" in courtly relationships or as a demonstration of contempt or disapproval.[4][5][6]
1 Used preconsonantally or beforeh. 2 Early or dialectal. 3Dual pronouns are only sporadically found in Early Middle English; after that, they are replaced by plural forms. There are no third person dual forms in Middle English. 4 Sometimes used as a formal 2nd person singular.
^Brink, Daniel (1992), “Variation between <þ-> and <t-> in theOrmulum”, in Irmengard Rauch, Gerald F. Carr and Robert L. Kyes, editors,On Germanic Linguistics: Issues and Methods (Trends in Linguistics. Studies and Monographs;68),De Gruyter Mouton,→DOI,→ISBN, pages21-35.
^Mossé, Fernand (1952), “IX. Elements of the Sentence”, in James A. Walker, transl.,A Handbook of Middle English[2], I. Grammar: Part Three. The Sentence,Baltimore:Johns Hopkins Press, translation ofManuel du l'Anglais de Moyen Age des Origines au XIVe Siècle (in French),→OCLC,§ 118,page94.