[dlwj]

I think the advantages and disadvantages are minor compared to other influences. Many poor immigrants for example speak 2 languages. Yet rich well travelled people also speak 2 languages.

This debate is only possible in the U.S. ... the majority of the world speaks at least 2 languages.

[guelo]

About half the world speaks more than one language at some unknown level of proficiency. The most popular second language worldwide is English because it is important for business. Since Americans already speak english they have less economic incentive to learn a second language.

[mikeash]

Really, there isn't a single other country on the planet where only a minority is bilingual? This strikes me as rather unlikely.

[hnhg]

The UK.