Well now we have a better clue who is delusional. As Juncker tells a conference in Florence that English is losing it's influence in the EU and so he would express himself in French.
English never had any real influence in Brussels till the Swede's joined and started saying "good morning" to everyone they met. Then the new former USSR countries joined and they were only interested in communicating with others in English.
Britain leaving the EU is not going to change the fact that, for better or worse, English is the international language of communication. Telling a bunch of Italians that he's going to speak in French is exactly what the EEC was all about, the EU was supposed to have cured that. Apparently some can't get over it.
I have spent so long in mainland Europe, living and working. I speak French with a French accent and a minimal vocab and grammar but enough to converse now. I speak German with a German accent for living and travelling but not conversing. But I have spent 20 years watching the people of the EU gathering together to talk. Bring two countries together and they sometimes talk in one language. Bring three together and it's English. Always!
Juncker is one of the old crowd. Those who firmly believed that the EEC (now EU), was French and that the Germans had a right to pay for it. They didn't want the UK because they knew that we would upset the apple cart. They should have thought a bit more about what expansion would do too.
Ah well. I'll leave him to his fantasy island and we'll get on with leaving the EU.