On the [Area 51](http://area51.stackexchange.com/) site, you can propose new Stack Exchange sites, including sites in languages other than English.

A few examples of existing proposals:

 * [Persian Information Technology and Computer](http://area51.stackexchange.com/proposals/2912/persian-information-technology-and-computer)
 * [Ubuntu (in German)](http://area51.stackexchange.com/proposals/30384/ubuntu-in-german) (with [some discussion on extending to Linux or even unix in general](http://discuss.area51.stackexchange.com/questions/1438/abgrenzung-zu-anderen-linux-distributionen))
 * [Software Development (in Portuguese)](http://area51.stackexchange.com/proposals/23539/software-development-in-portuguese)

Note that a site would not have to be specifically about Ubuntu — you can ask Ubuntu questions on a site about [unix in general](http://unix.stackexchange.com/) or even about [all computer hardware and software](http://superuser.com/). My recommendation on the right size of a site is unix in general.

If you decide to create an Area 51 proposal, tell all your Portuguese or Italian-speaking friends! The site will be created if and when it has a critical mass of committed users.