It doesn't mean you have to become an expert in all the languages of the places you are going, is impossible, but knowing the magical words: thank you, please, excuse me, hello, etc. is not only advantageous but is also polite. You can totally see it in people reactions when you approach them in their language, even if you suck at it, trying makes a huge difference. Some people in some countries even get annoyed when someone addresses them in english assuming they should speak it, well it actually the other way around, if you are visiting a foreign country the least you can do is to learn the basics. Even if you only learn "I'm sorry, I don't speak russian" is much better than just enter the russian grocery store and order in english as if you were in London.