During the eighteenth century, language became an increasingly valuable commodity for the construction of identities and the negotiation of relationships with others. Additionally, letter writing had emerged as a crucial means of maintaining relationships and forging deeper intimacy between individuals, and correspondence thus constitutes a rich resource for the study of language variation and change in relation to (social) identity, with forms of address as a key strategy in this respect. The current paper examines expressions of direct address and self-reference in Late Modern English ego-documents, more specifically two sets of letters involving Mary Hamilton (1756–1816), sub-governess at Court and a member of the Bluestocking circle. For each set, we discuss intra-speaker variation in the context of both the individual participants involved and the structure of the letters. The findings reveal different strategies through which Hamilton and her correspondents construct their identities and negotiate their relationships with each other, for example by using nicknames and terms of endearment, omitting signatures, or through changes in lexical choices over time.