I don't think there's a right to be taught in the language of your choice, the same way you can't decide which subjects your children will study. At least not in Spain.
> mayors who do not support the referendum are being harrased by the radicals
Maybe you should look at what's happening to those supporting it.
The mayors who support the referendum are just being called to declare by the tribunals and being told that what they are supporting is illegal.
But there is the right. Is in the Spanish Constitution. Article 3.
"1. Castilian is the official Spanish language of the State. All Spaniards have the duty to know it and the right to use it. 2. The other Spanish languages shall also be official in the respective Autonomous Communities in accordance with their Statutes. 3. The wealth of the different language modalities of Spain is a cultural heritage which shall be the object of special respect and protection."
And if people holds sacred the contituion, the TC didn't invalidated the linguistic immersion, it is constitutional