Re: Trying to Change/add new unit names
Welcome to TWC!
I can't give you advice about The American Revolution specifically, but I can suggest what to look for. When you want help with modding, it's worth having a look in the Empire Mod Workshop, particularly in the Tools, Tutorials and Resources section. In Tools, Tutorials and Resources, there's list of basic how-to guides for new modders, including one on how to create a new unit (unfortunately, the screenshots have gone, as the file-hosting site which was used closed down, but the text which remains should provide enough information to work out what to do). The guide on how to create a new unit includes (step three) a way to name a new unit. This explains that, to name a new unit, we need to create a modified version of the game's localisation file - if you play the game in English, this is patch_en.pack.
This means that, if you're looking to edit/add unit names to The American Revolution, you will need to find the modded version of the localisation file which The American Revolution uses, and to edit that file. It is likely to end _en.pack, so it could be something like TAR_en.pack (I'm just guessing at the name of the file, anything could come before _en.pack).
Good luck!