After reading the latest news from Belgium on the inability of Flemish and Walloon political parties to form a government, I am wondering how many successful multi-lingual states actually exist. That is, how many genuinly multi-lingual states - those with a significant percentage of the population speaking different languages - do not have persistent political friction due to the language/cultural differences?

The only example I can think of is Switzerland. By contrast, the tally for failures is quite large. Leaving aside African states, which I am not very familiar with, here are some examples which immediately jump to mind:

• Canada: despite recent defeats at the polls, support for Quebec separatism remains at 40-45%. This number has been essentially unchanged in recent years.
  
• Spain: Basque separatism has been a steady source of terrorist attacks over the last few decades.
  
• Czechoslovakia: defunct after the first free elections.
  
• Yugoslavia: an extremely bloody breakup into five ethnicity-based states and one multi-ethnic state.
  
• Israel: 20% of the population speaks Arabic. Racial riots are not uncommon.
  
• Moldova: fought (and lost) a civil war with a Russian speaking province in the early 90s.
  
• India: being a blend of a number of different ethnic and linguistics groups, India has had a large amount of separatist terrorism over its history.
  
• Sri Lanka: in a civil war with Tamil-speaking separatist insurgents.
  
• Indonesia: fought bloody wars over East Timor and Aceh. Both of these province have a distinctively separate linguistic identity. The former conflict was effectively lost, the latter is still continuing.
  
• Cyprus: after many wars, divided between Greek and Turkish enclaves.
  

This list is of course not comprehensive and there are many other examples out there. One pattern is that language-based frictions vary in strength based on the number of speakers of the language (for example, compare the relative weakness of Breton nationalism in France with the relative strength of Basque nationalism in Spain) and on the linguistic similarity between the various language. If the languages are different enough though, the conclusion seems to be that language-inspired political frictions never work themselves out, except by violence or separation.

By contrast, I am tempted to say that the reverse was true in the 19th century. Most Italians and Germans speak the standardized version of their languages (possibly concurrent with their local dialect). But standard Italian and standard German were not spoken 200 years ago; they were successfully foisted upon the population by governments that sought to strengthen national identity.

Such a thing does not seem to be possible now due a freezing of national and linguistic identities. Its hard to predict what trends will take place in the future, but if current trends continue, its hard to be optimistic about Canada or Belgium.