Translating the mod in other languages is great, and of course we won't stop you if you'd like to.
Nevertheless, there are some problems, why we hardly can make it official.
If we offer something official for download, those who download it will expect support and some more things, which we can't guarantee, because we have neither time nor the language skills (obviously).
But that does not mean at all that you can't do the translation as kind of a submod.
To give you some basic information:
The ingame text is saved in the lotr.str, a huge file, containing every piece of written text ingame, and even many which aren't used anymore. This file can be changed without having a missmatch error, when playing multiplayer, which makes different versions for different languages no problem at all.
The lotr.str of Edain contains about 25000 entries, the one of the original game only about 10000. With every patch, there are about 20 to 50 new entries and 100 to 200, which were changed. With much help from the comunity and those 10000 entries which we got from the original game, we still needed approximately 2 years to get to a point, where the English version was finished enough, that we could eventually start testing it.
You see, that is an enormous amount of work. So I would suggest, to start with Google translate, to get at least a basic and then to begin with those texts, which aren't understandable.
If you have any specific questions, I will be glad to help you.
PS: English was my second worst subject in school (directly after French), so I don't really know, how I ended up being the one in charge for the English version
Edit:
The Edain translation needed more than three years, many users helping with the translation, and 1-2 teammembers working on it, too. Also, with every patch there are quite many new and changed lines, so it is nearly a full time job, just to keep the translation up to date.
If you don't have a team with 3-5 persons, I doubt it will work. Therefore Google translate might be a good basic. You can see the first effects ingame, and then you can correcting bugs, or rewriting those texts, which are hardly understandable at all.
If you want to do a full translation, the best way to start would be to integrate all those lines, which weren't changed since the basic game.
And then I would start with one faction and try to translate everything in it.
When I started taking charge of the English translation, I wrote myself a Little program to help me. This program can return all those texts which aren't translated yet, it can insert new translated texts, it can return all texts, where the text or the description contains a special word, and some other things. Sadly I made it only in German. But if someone wants to try it, I can offer it.
Concerning the search which one is the correct text.
All the texts are in the lotr.str, which is in the englishpatch201.big. This is the only file you have to modify to change the texts.
Most texts are used in the buttons. These buttons are listed in the commandbutton.ini and \includes\commandbutton.inc.
Which commandbutton is used in which set, is defined in the commandset.ini and \includes\commandset.inc. And which hero is using which set, is defined in the ini of the hero, for example CommandSet = EmptyCommandSet.