my only foreign language is English. and very basic German, just enough to be able to understand and sing Rammstein songs.
And actually i don't see the point in learning many languages. It's a huge time investment and what do you get in the output?
Most of the planet speaks english, so english is quite enough for any practical purpose like travelling and socializing with people from other countries.
The only reason i can think of is reading fiction literature (watching movies, listening to music) in original language. From my experience, once you read both the original and the translation of any book (or movie) you understand that a translation never comes close. A lot of author's style and wit is lost in translation.
But being a good reason, still it's not good enough for me to devote a significant portion of my life to learning another foreign language. IMHO it's better to polish the one you already know. In my case it's english and i try my best to practice it any time i can. (hope i do a good job here
)