Can't apply language
In ubuntu I can't apply any language system wide. Though I have installed language packAs you can see those language are not selectable . I am using ubuntu 17.04
1 Answer
You must drag and drop the languages in the list into the preference order you desire. Applications will then use the topmost language in the list which they do support.
Note that the English element is the default language supported by every package. Therefore all languages in the list below this element are disabled and ignored.
So what you have to do is to either drag your Hindi (or whatever that language is, I don't know) language elements up, or the English one down.
As @Gunnar Hjalmarsson pointed out in his comments, it is not allowed to put any non-English languages between your highest enabled country-specific English language element and the default English element, because that would make few sense. See the comments for his more detailed explanation.