Earlier quoted context omitted.
Actually context matters here. If some one from USA/UK/France, for example, learns a new language it definitely is a surprise. May be blows the mind is not the right word. On the other hand, it is common for people from Southern India to know 4 or 5 languages and it is not surprising.
We do learn 2 foreign languages in France during school (English + German/Spanish/Italian/whatever) so I'm not really sure why it would be a surprise to hear a french speak another language. They might suck at it though.
French people "learn" german and english but are terrible at it even after learning it for 10 years.
Scandinavian people learn english and are actually fluent with a good pronunciation after a few years.