The European Union should introduce one working language. With just one uniform language, it will become so much easier to conduct day to day business and they will be able to get much more stuff done. Many people already have one language in common, so it would be easier to do business that way.
Europe is diverse in culture and in language. Every country and every group of people has a unique history that has influenced everything from cultural tradition to language. None of this can be lost. Europe is diverse, and this fact needs to be embraced. Every language is significant and must be preserved.
While it is impractical to use every European language as a working language, it is possible and sensible to have more than one. English, German, and French are the most sensible options as each is spoken in multiple member countries, as are the most widely understood second-languages within the European Union.