When does a region have the right to declare independence?

[ingemann]

First the irony that a American of all people claim that to have legitime reason to separate from a country you need to speak a separate language are hilarious.

Second as for Gaelic not been widely used enough, that's very well, of course Gaelic was never or only for a very short period the majority language of Scotland (depending on when you say Scotland was founded and whether people claim Pictish was Gaelic). Historical the majority language of Scotland have been Scots English until the 20th century. So to claim that Scotland have no right to independence, because only a minority speak Gaelic are like claiming that USA have no right to exist because only a minority speak Pennsylvanian Dutch or Cajun French.

Third and this is only my opinion about your question. A nation exist if the people say it exist. Most Irish people speak English, most Americans speak English, that doesn't mean that they are not a separate people from the English. As such I think that any region which can claim a majority for separatism have a right to separate, whether they speak their own language or not.