What almost all accounts of standardisation histories have in common is a focus on printed, formal or literary texts from writing elites. While Haugen identified the written form of a language as “a significant and probably crucial requirement for a standard language” (Haugen in Am Anthropol 68:922–935, 1966a; Haugen, in: Bright (ed) Sociolinguistics, The Hague: Mouton, 1966b: 929; cf. also Haugen, in: Asher (ed) The encyclopedia of language and linguistics, Pergamon, Oxford, 1994: 4340), and while print certainly constitutes an important instrument for the dissemination of codified norms, it remains to be established what role hand-written texts played in standardisation processes. In nineteenth-century Europe, mass-literacy, which is generally seen as a precondition of standardisation processes, was only possible because large parts (or even the majority) of the population learnt to write (and read) hand-written texts. In the vast volume of private texts that were produced during the various wars and emigration waves of the nineteenth century, not only codified norms, but also (regional) norms of usage were widely transmitted. Private letters and diaries, in particular, have proved to be a valuable text source for the investigation of such norms and their diffusion (cf. Elspaß, in: Hernández-Campoy, Conde-Silvestre (eds) The handbook of historical sociolinguistics. Wiley-Blackwell, Chichester, 2012). With examples from a corpus of German emigrant letters, the present contribution will try to demonstrate that grammatical norms of usage which were literally not visible in printed texts at the time, but which are now considered standard, formed part of the standardisation process of German.