Here's a depressing (albeit anecdotal) read. It's about how native English speakers, who also fluently speak another language like German or Korean, have discovered that Germans or Koreans are actually insulted when an English speaker speaks to them in their native language.
As a Canadian, I have become somewhat accustomed to going to Montreal and finding it nearly impossible to speak French with anyone. I am bilingual, having spent my entire school life in French immersion, but it's obvious that I was not brought up in Quebec, and so I've found it a challenge to speak French in Montreal.
Outside of Montreal it's a completely different story, but it used to really frustrate me to have to speak English to Quebecois who could barely do so, just because they were offended by the fact that I could speak their language, and my French was much better than their English. This kind of suspicion, I think, is part of what's motivating the PQ's recent decision to ban religious symbols from public spaces. But this was the mid-1990's, the height of the Separatist fervor and the 1995 referendum, and so I chalked it up to that.
As for Germany, my experience has usually been pretty positive. People will respond to me in English when I begin speaking with them, but I usually think they are doing this as a courtesy, because when I respond again in German, they respond in German. Most people I encountered in Germany seemed somewhat relieved that they didn't have to speak English, in part because although nearly everyone speaks it, it's easier (for all of us!) to converse in one's native tongue. Often people seemed relieved to be able to speak German instead of English. I might not have felt relieved, but that was my problem!
But there is a larger issue here, one that is raised in the post. I was speaking to some Medievalist friends yesterday, and they noted that the language requirements in their department have been watered down over the years, because students are not coming to the program with much in the way of foreign languages. We lament this, but the fact that Universities are closing down their language departments and schools no longer teach Latin means that it's quite likely, even in Canada where everyone "learns" French, to have a student population who has had no meaningful exposure to a second language, where it's messed up their brain a bit and made it soft for learning other languages.
I think this is a really big issue for those of us in the North American Humanities - it's not just that people (maybe) don't want to speak with us in anything but English when we are abroad, it's that really learning a bunch of languages, when you are a native English speaker, is a cost you do not have to bear, because you can always rely on English anyway.