We've had a look at this issue and think it is because we needed to re-compile Pango (font library) for it to work correctly on all Linux systems. We've tested this successfully on Fedora 16 x86, but would appreciate your help in testing on your own operating systems if you have had font problems with the game. The faster we get feedback on this, the faster we can push a fixed version. Thank you for your help!uoc_font_fix_2013_01_27.tgz
Included are some re-compiled versions of the Pango libraries shipped with the Unity of Command game, which should solve this issue.
Copy these files over the original versions in 'Unity Of Command/bin'.
For the Steam beta installation, this will be:
'~/.steam/steam/SteamApps/common/Unity Of Command/bin'