A couple of people have mentioned greater unification, but is Belgium not an example of the barriers of language and culture?
Belgium's case is a common misunderstanding. It actually proves that the EU is necessary and that the EU should move towards a federal entity. If there are talks of splitting Belgium at all it is merely because it would not change much for everybody involved, except for the taxes. If the country splits it won't affect borders, visas, work permits, currency, companies, and so on, because all these things are already managed at the EU level. Most of the ministries (economy, education, culture, etc.) are already federalised. The argument between Dutch- and French speakers is almost only about money. In Spain, Catalonia has its lot of separatists too, and the main reason is also money. Richer regions don't like to share their taxes.
How long has Belgium been unified as one nation and yet still this rift remains, surely if they had united under one language their differences would have faded over time as one laguge would have meant greater cultural exchange?
Belgium was already a Roman province. From the 4th to the 9th century it was unified under Frankish dominion. After that it was divided in small counties and duchies, but they were reunified again under the Habsburgs until the French Revolution. Belgium became an independent monarchy soon afterwards. So you could say that it has been a more or less unified entity since the Roman conquest 2000 years ago. The linguistic confrontation is a recent issue dating from the 1960's onwards, when Flanders overtook Wallonia as the country's economic powerhouse.
It would seem to me people have to mix to create a new culture when political and social boundaries change. In the UK I think the Union has worked for so long as we all speak one main language at home and at work (accent variation is exagerated, Scots is not a language). Over time the national identity of Britishness has formed and created a new cultural identity.
So I think for a united Europe to work first you need:
1. A unifying language, which will lead to greater cultural exchange
I strongly disagree. Languages are a richness to preserve. A single language will certainly not unify opinions and viewpoints. Just look at how Americans were deeply, almost viscerally, divided about G.W. Bush. British people hold the most dissenting and polarised opinions of any member state regarding the EU. It is an illusion that speakers of a same language think alike. It may be true for a few elementary things related to language processing, but not for political opinions.
Even culture and lifestyle are only loosely related to language. Just compare British and American cultures and lifestyles. It's hard to find two Western countries more dissimilar. I sometimes think that the US culture was built as an anti-thesis of British one - perhaps as a way of distinguishing themselves and clearly breaking off with the old motherland. Each is what everything the other is not. Americans are cocky, loud, extroverted, extravagant, very sociable, not attached to history and traditions, patriotic, and inward-looking as a nation. British people are modest, discreet, reserved, thrifty, loners, very attached to history and traditions, like to criticize their own country, and very open to the world and outward-looking as a nation.
