In recent years Professor Juhani Härmä has studied a body of material that has proved to be a treasure trove, albeit somewhat difficult to manage due to its abundance. For some time ages there had been discussion as to whether French-language material of Finnish origin could be found in Finland, material which is largely found in countries like Sweden. Härmä very much doubted that such material existed.

A few years ago, Emeritus Professor of History Matti Klinge drew Härmä's attention to the French-language letters written by Finns in the collections of the Finnish National Archives. Although it is difficult to get information on the precise amount and composition of the material, the National Archives has thousands of such letters, not to mention those held elsewhere, including Sweden.

The letters offer many points of interest to a language scholar. But however fascinating, those Härmä is studying have received little attention, probably for no other reason than that they are written in French. Apart from the letters, other materials can be found in the archives which indicate that in recent centuries French had served as the medium of communication and culture for the Swedish-speaking elite in Finland, as it had elsewhere in Europe. The role of French can already be seen in the dedications of the dissertations of the Royal Academy of Turku in the 17th century. When Finland was a Grand Duchy of the Russian Empire, the Russian officials and Finns used French as the medium of communication, as can be seen in 19th-century French documents.

The letters are also of great linguistic interest. A prominent feature in many of these is code-switching, i.e. the usage of French and Swedish in the same letter. The writer may start in Swedish but conclude in French, and the letters written in Swedish are full of French words and phrases. Examination of the French wording of the letters suggests that it was possible to learn the language as well as, or better than, today, even though there were no proper textbooks back then, let alone access to the various illustrative and audiovisual materials available today.