I'm a <i>big</i> fan of bilingualism but if you're living in America and inclined to do business primarily in America, then the advantages of it are not so great next to the <i>prodigious</i> effort required to learn another language.  Most Americans study Spanish, but then a) countries and people who speak only Spanish are not typically great economic prospects (compared to, say, Japan or Germany or what have you) and b) supposing one were to study Spanish and use it for one's career, one would be competing with American native speakers of Spanish who probably speak better Spanish than you.<p>If a country like, e.g., Japan/China/South Korea were a skip over the border instead of a 10+ hour plane ride away, I'd recommend every single person to study Japanese/Chinese/Korean.  In Sweden, even if English weren't the lingua franca for Europe, you'd still be close physically and economically to multiple English-speaking countries.