Some people can get by with discipline instead of being forced to speak their target language. I spent a month in Spain and forced myself to communicate only in Spanish, even if the people I met knew English or French (the two other languages I knew better back then). I even deliberately chose touristic information in Spanish instead of the two other, including audio guides and stuff. The funny thing is, I have no idea how easier it would have been with English and/or French, since I didn't even ask if people spoke other languages than Spanish!
But I agree that people without discipline should jump in the water and go to a place they simply can't rely on their native language.