I don't understand why you're getting Russian in a pacific mission, but yes, IL2 1946 is very much a stand alone single player game, although online flying is available and is outstanding. There are campaigns available for all air forces in the standard version so you should love it.
Did you install from a disc or download? Maybe you have a corrupt file either way, so I'd say disable your AV and re-install.
Also, if you're running windows 7, disable user account control, and don't install the game to a default directory. Create your own file for it and install the game to that file. If you're still running XP, ignore what I just said.
P.S. Always select 'run as administrator' when installing.
Hope this helps.
PPS, cross post sorry, there aren't any British or american european campaigns in the standard game, but community built campaigns are common. Try 'Mission4today.com' for downloadable campaigns and mods. The game has been going so long, it's a minefield, which will take a bit of researching.
PPPS. for campaigns, click 'pilot career' then click 'new' then select your country and take it from there.