Army Men RTS has been officially translated on 6 languages. In this thread I will share with you language files, which I have found in various versions of the game.
Features list:
Translated text (except for Japanese, see below): interface, campaign, missions
Translated voice acting: units, campaign
Translated textures: bootcamp
A few notes should be added on the Japanese language. It was ported directly from PS2 version, since a japanese version of the game has not been released on PC. (Thanks to ZEN_Ivan. for providing PS2 game image file.) Due to this fact some voice dialogs may not sound appropriate in Boot Camp mode. Also PS2 japanese.dat is not supported at the moment because Japanese symbols use WideChar (2 bytes) format, but the game executable can read only AnsiChar (1 byte) format. The problem can be solved only by rewriting the executable code.
In order to install, extract chosen language file to your Army Men RTS root directory. This will replace your 'language.cfg' file and add necessary language data.