To follow up on the comments of Pix, I, too, try to have at least a basic understanding of the language native to the country I am visiting or habitating. At this time, I live in Paris and my French is extremely fluent, if accented. (I am American, BTW...) I also speak Italian, Spanish, Arabic, English (of course) and am in the process of learning Portuguese. Having a basic knowledge of multiple languages is an extremely useful thing as it enables one to navigate independently and with relative confidence wherever one goes. It is shocking to me that there are so many people who move to other countries withabsolutely no base in the language they will be speaking. The greater part of my students here are people who plan to move to an English-speaking country within a certain time-period and require a crash course in English. At the moment, my students are splti right down the middle between those requiring American English and those requiring British English, but I take my hat off to these students for putting forth the effort to get the best possible base before they depart.
And not to be critical, but the subject of this thread should actually read "How many people actually speak the language of the country 'they're' in?" To use the word "their" indicates ownership, wheras "they're" is the shortened form of they are.
Sorry - I tend to be a bit maniacal about spelling! (I say this with a grin, as I often re-read my posts and messages and find to my disgust that I have typos all over the place!)
And to expound on the comments of those who wrote that they often have trouble finding words in their native languages once they speak other languages, I agree. Obviously i am a native English speaker, but after 4 years of speaking French on a daily basis, I often find myself unable to adequately express myself in English on certain subjects because there is just no English equivalent for the feeling I wish to express. I also have the bad habit of dropping into French when I am speaking to my American friends or English when I am speaking to French ones. The subsequent looks of confusion are quite funny, actually, but luckily people are used to my ditziness and just roll their eyes and remind me what language I am supposed to be speaking. On the flip side, for my French friends the conversations with me are helping them learn more and more English as a simple survival skill for holding conversations with their amerloque friend!