The Channel islands and the Isle of Man are not EU members, English is not a first language on Cyprus and Malta and an alternative language in Ireland (Irish eurocrats speak about Irish and "the way Irish people pronounce English"). That leaves the UK as the only member-country where English is the first and only language, so German, French and maybe Italian are more important languages. If Turkey accedes, Turkish would also become more important than English in population terms.
In practice, since many of the institutions of the EU are in Brussels and Luxembourg, where French is spoken, you will find that you can communicate in French with the large majority of the people who work there. Many Walloons and French will even have trouble communicating in English. In addition, since Britain has often proved to be a disloyal, even obstructionist member-state, there is a tendency to avoid English as a way to express disapproval.
While a3v1 is right that all languages are considered official and equal, it might have been otherwise. At the time of the accession of Malta, the precedent was on the table. The Maltese wanted some concessions for giving up Maltese as an official language. They got the concessions, but the EU side forgot to take the Maltese concession. This was a major and expensive blunder, because some Eastern and Central European countries were reportedly willing to give up in the language question also, but maintained it after Maltee got official status.
All of which reminds me that the nickname for a quarter in the US is 2 bits, which is 2 reales or 1/4 of a peso of 8 reales, the father of the USD. The nick lives on in a number of Caribbean Islands. I also wonder whether quarter and dime are nicknames or names of coins not adressed by their denomination.
Also, there must have been more nicks for British coins than I remember: Joey (4d.), Bob (1/-), florin (2/-) and guinea (?1.1).
Peter