It might take another 50 years, but we, eventually, will become a single union. This are interesting times
Now I don't want to say we all have to speak English, but it's, economically, the logical language to go for (http://www.andaman.org/BOOK/reprints/weber/rep-weber.htm) and entire EU youth are watching US movies + US tv shows and thus US culture 24/7. I hear Spanish kids making translated jokes (from dubbing) from American shows. Economy wise it would make sense to just make the union speak something which can be used in international business. And then of course the things you speak off as well to make it 1 union.
Well... not enough labour mobility without a common language and without labour mobility no optimal currency area. Somebody should really have thought this through...
Similarly, virtually any company in Europe that has more than one accepted work floor language, has $NATIONAL_LANGUAGE and English. And any company where the work floor language is not the national language, it's English.
Really, this battle has long ago been won. Only some archaic government institutions like the EU itself pretend that languages other than English still make a chance at becoming the lingua franca of Europe. Whether or not the UK currently is in a Euro-mood does not influence this at all.
Oh, and you forgot about Ireland.
They have a funny accent though.