In some, but not all, my strategy games that have French or German accented letters in their texts, the accented letters fail to be represented correctly on screen. Most recently this problem occurred with Silent Hunter III, a licensed copy (?) of which I bought here in Moscow and to which I added the "Grey Wolves" add-on. The German umlauted letters (Ää Öö Üü) and the character known as "scharfes-S" (i.e. "ß") appear on the screen as Cyrillic letters. However, I have other software having umlauts and French accented letters that are represented correctly on screen, e.g. a copy of an English version of Silent Hunter III that I bought here.
For historical accuracy freaks such as I am you can have your crew in Silent Hunter III speaking in German as well as English or Russian or whatever, depending where you bought your licensed copy, and have the game texts in German as well if you so choose.
This problem also occurs with a Langenscheidt and Düden electronic dictionaries that I bought here.
I have discussed this problem with several expats in Moscow and they all have the same problem with accented letters; they have sought advice off computer experts, but to no avail.
I've tinkered around with the languages parameters without success.
I did solve the same problem long ago that I had with the Sid Meier stategy game "Waterloo" (which Meier game, together with "Gettysburg" and "Antietam"doesn't operate on Windows XP), but I'm not sure if I can remember how I did this. I think I re-installed the OS (which was Windows Me) with English as the operating language.