change of language

hi
i'm a new user and i have several website and weblog with WPMU. every thing working good and have no problem so far. now friend of mine form another country asked me to design a new website with a different language. so, i just need to change a website language without effecting anything else in my network such as super-admin dashboard or other weblog admin language.
1- can i change wordpress theme's language without changing wordpress admin bar language?
or
2- can i change wordpress dashboard language just for a single blog or site . not for the entire site network. for example if i have test1.example.com?

3- does "Languages for WordPress" plugin change admin dashboard language and theme at the same time?

thank you in advance for your help