I agree with David Watts, and would like to add the following.
The word the would also refer not just to a translated version, but to any work in that language as well as in some cases (as Kris mentioned via comment) the language itself.
Translated from the German.
This would refer to the German book, the German version, the German text, etc.
I speak German
This refers to the language itself
However, one may also use the article when referring to an instance of the language in an instance like this:
The German I know isn't very useful.
Take care when using 'the German' since it may seem to a listener as if you are referring to a certain German person