Not sure what you want, by default ezp 4.1 has url aliases specific for every language. This means if we have a content object (for example node 2) translated in different languages:
a.) russian -> ru_url_alias
b.) french -> fr_url_alias
and you configure fr.example.com with french as main language, the url for node 2 would be fr.example.com/fr_url_alias and in a similar case in russian: ru.example.com/ru_url_alias
So the url aliases are different, but point to the same node in a different language.