But, what do you mean by the language?, the language of the dll wrappers?, because if it is that, don't bother. I mean, my system is in spanish and there are no problems.
What it is the important of the language of a dlls (any dll, not only wrappers) is mainly for messages of errors or informational purposes. You can have dlls of every language in your system and still will run.
I show you a simple example, run dxdiag and go to the second tab, are all files in German? I answer you: no. There is not need.
I'll bet you have loads of programs with dlls language in english right now in your system.
Obviously, you don't want a dll in japanese, but at least in english...