What do you call someone who speaks three languages? Trilingual. What do you call someone who speaks two languages? Bilingual. What do you call someone who speaks one language?I was smiling and nodding, but at this point, you've all heard the punchline. It's an American who speaks one language.
No: French. Apparently that's a known joke in France, but "French" is their punchline. They tell it in the UK also, but "British" is their punchline. I seriously doubt the Dutch would tell it in reference to themselves.
Knowledge of foreign languages really depends on your culture and circumstances, but what you want to know is whether or not you'll need to learn one. The answer is a frustrating "it depends". In addition to my native English, I speak French (not fluently, but you can drop me in the middle of France and I won't have too many problems) and am now studying Dutch. I have never needed French for living abroad, but I was living in the UK. Now that I live in Amsterdam, I was pleased to learn that my company offers a language program, but then I found out it was to assist employees in speaking better English. Dutch may be the official language, but there are so may expats here that English is the standard in many companies.
So you can get by with just English, but it tremendously limits your opportunities. I was recently offered a job in Paris and they made it clear that speaking English was fine, but that's the exception and not the rule. If you must have Paris, speak French. Have you fallen in love with someone from Spelancato in Corsica? Speak French. There are many lovely destinations in South America which are going to require you to speak Spanish or Portuguese. Does Casablanca flip your wig? Better learn Arabic, Berber or French (hmm, lots of French sneaking in there. It was a coincidence in my choice of locations).