This file can be found in the str folder, extract the folder and the file into your data folder and the open it with Notepad. This file controls all the ingame texts, the text to the left should not be editied but the one to the right can be.

Example, the line:

EXIT EXIT can be changed to EXIT LEAVE GAME for instance

Any other name can be edited in the global.str file. This includes all the tooltip names, mission names (Saving Private Smith etc.) etc. etc. Basically anything you can find in the global.str that is also present in the game (the horse for instance seems to be a removed object).

If you go through the global.str you can find references to a versus mode, i.e. allies versus germans. Unfortunately though it seems this game type was never implemented in the full game, who knows, maybe we will see this in Commandos 3.