I think that a problem of a seperate forum would be, that not as many people as in this official forum would be able to help with problems. That's why i would suggest an enhancement to the official forum :

My suggestion for the problem of people who have another native language as english or german (i think 10% of all posts are in german, which is in fact quite unfriendly to other users who don't speak german ^^). Is that the main forums should stay ONLY english. But there should be sub forums in the official forum for each other language. Like for example an Arab user forum (i have to admit that i don't know, what languages are spoken in the arabian peninsula... (will have to search wikipedia for this ^^)).
And in each of this subforums, posts are posted in the corresponding native language. And for every forum at least one user who speaks both languages fluently and visits the forum frequently - like you - should be entitled as moderator.
Now that there would be subforums for let's say, german, french, arabic, turkish... People who only speak their native language fluently would be able to post in the forum for their language.
And now comes the difficult part of my concept :
There would have to be users, for example the moderators of these forums and other users who are trusted and speak both languages fluently, who would translate a post to english and post it in the main forum (if needed). and then would translate possible answers in the main forum back into the forum of the certain language. Thus, these special users who translate between the two languages and post in the main forum for users who can't speak english would be the interface between users who don't speak english and the main forum !

But as one can see this concept may be flawed as these people who translate between the two languages, would have quite much to do...