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I still strongly believe that we Europeans need to learn and speak a couple of our Union languages, other than English.
with the increasing dominance of english, i believe, there will be no need for an additional EU language other than english. however, there will be need for chinese and indian language. i saw about 20 german in Beijing studying chinese. the needs come from economical reasons, since, i guess, chinese (and japanese) people hardly speak/learn english.
in ottoman, french was popular in 1800 's, after revolution. The german was 2nd lang. when german system was dominant in army. in republic time, you could select one of french, german or english in the schools as a second language. these days, almost everybody selects english and most of the schools provide french and german only for 3rd language after english.
with rise of south american economy, spanish may also be more important in the future.