Historical sociolinguistics has favoured the interest in tracing heterogeneity and vernacularity in the history of language, reconstructing the sociolinguistic contexts and directions of language change as well as socially based variation patterns in remote speech communities. But this treatment of language variation and change macroscopically, longitudinally, unidimensionally and focused on the speech community as a macro-cosmos can be revealingly complemented with other views microscopically, cross-sectionally, multidimensionally and privileging individuals and their community of practice as a micro-cosmos. This conveys a shift from the study of collectivity and inter-speaker variation to that of individuality, intra-speaker variation and authenticity. The aim of this paper is to show results of the microscopic investigation of intra-speaker variation and the use of stylistic choices as linguistic resources for persona management within the micro-cosmos of late Medieval England, through the application of current multidimensional socio-constructionist models to historical corpora of written correspondence. The study is carried out through the analysis of the behaviour of the orthographic variable (TH) in the letters written by members of the Paston family. In addition to tracing language change, the data obtained from private letters provide us with the possibility of reconstructing the sociolinguistic values in medieval times. Ultimately, this study’s contribution is to account for the social meaning of inter- and intra-speaker variation in the sociolinguistic behaviour of speakers at the individual level as a linguistic resource for identity construction, representation, and even social positioning in interpersonal communication.