The 7% figure quoted is, I would suggest, are the ones who stood up for their right to choose castellano as the language that they would prefer their children to be educated in.
Many more decided to take the easy way out and not to argue with the powers that be, and those who did, were browbeaten and politely told ( threatened) that if they kept on insisting they may find their children being moved to another school, sometimes miles away from their previous one. I would beg to differ about Franco trying to eliminate minority languages or dialects.
What he did do was to impose a strict policy of only allowing castellano to be spoken and written in all government offices ( and schools)all over Spain, which , to me, seems a very sensible thing to do. I think that Mr Tunnell will agree with me that the strength of feeling about the imposition, or not, of castellano amongst the local population is far more virulent amongst those who were born long after Franco passed away than amongst those who had to suffer his, some would call, undemocratic impositions. Why and for what reason would be a good theme of discussion.
Yours sincerely, Simon Tow