You must also be fluent in English to make a good translation.
In order to do it you must start by reading the guidelines carefuly
http://files.msgplus.net/data/TranslationGuidelines.doc
You should now contact Patchou and ask to be added as a translator and so you'll start working as soon as he adds you and give you acces to the new version. I don't know if you can start right now on version 4.0, but for the next one i think you'll already be on.
Anyway, don't start translating v3.6. But get used with mp! features and you can even start making making a translation list of the feature names just to start working on it.
When the work is finally done, post it on this forum so we can help you on looking for technical mistakes.
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