Europe Needs A Common Language
This single biggest obstacle to pan-European federalism is the lack of a common secondary language
which everyone can easily learn and understand.
This would be a lingua franca which would not actually replace the various native national and regional languages of Europe
but would be a common second language
which all Europeans could use to speak and write to those who with whom they do not share a national or regional language
much as educated Indians use English as a common second language and lingua franca to bridge the many ethnic and linguistic barriers
which are present in India.
However although English has de-facto become a type of European lingua franca
it is a very poor choice as a pan-European language.