Even though I'd not participate in those sites as I'm no where near fluent in anything but English, I think after a period of time — another 6-8 weeks6-8 weeks months? — to let Ask Ubuntu establish itself, those could be tried and might be successful.
However, I hesitate to fracture the community. It's been pointed out here (comments on another answer) and elsewhere (including meta.SO; don't ask me where, but please comment with links), it can be better to have more people communicate, sometimes poorly, in English rather than never get an answer because it's on a separate site.