I want to be able to switch between my input languages, but I can't drag and drop the languages in language support because the languages seem to be greyed out, what should I do?
In Language Support you can change the display language. The place to control the input language is System Settings -> Text Entry.
They are grayed out below
English, because everything is available in English.
The drag and drop is the ordering in which a language is used. So you can display everything available in Irish, the remaining in German and everything that isn't available in German in English finally - or sth similar.