Translation variations for back and front-end

Please, I would like to know a way to setup translations for my back and front-end at the same time, based on domains, sub-domains or sub-directories.
I want to have a wmps in different languages, offering back and front-end translated at the same times. The plugins I know are translating only the front-end. My subscription finish 16 th. Please let me know with the more information as possible, because I will not be able to ask again soon. Thank you!