Each page must be identified by its own language. For example, English pages begin with the keyword En:.
If you want to add articles in a new language, please use the same syntax.
Their again, same rules !
To keep it simple, pleasez consider that if you create a page in your language, there is some chance that the same page will be needed one day in an other language. Do not wait ! Whenever you create a page, copy-paste it in other languages, translated if you are able to do so, in English otherwise. On last hand, in your own language. We just will figure that somebody will actually translate it.