Language difference is the obvious but vaguely surprising thing I noticed in Columbia. Portuguese to Spanish is a one-way street. Portuguese speakers can understand most Spanish, but Spanish speakers do not understand much spoken Portuguese. My Brazilian colleagues told me about this and I found it was true in Bogotá. People spoke to me in a language I more or less understood, but my responses were met with puzzlement. Portuguese, especially the Brazilian variety, uses vowels in a more exuberant way.
The boundaries of language are interesting. Some dialects should qualify as languages and some languages are really just dialects. There is an old saying that a language is just a dialect that has an army and a navy. When I spoke Norwegian, I found I could also understand Swedish w/o too much difficulty. Written Danish is almost identical to written Norwegian, but the spoken language is different.
Of course, some things called dialects probably should have their own language. I read that Chinese “dialects” are mutually unintelligible. Like Danish and Norwegian, the written languages are the same or similar, but the spoken languages are not. I have had some problems with English. There were people I could not understand when travelling in the UK.
My first language shock came when I was nineteen. I hitchhiked from Wisconsin to South Alabama. It was a dumb idea. I was not prepared and I had only about $15. I was trying to go to Florida, but I didn’t have a map or much of a plan. I ended up on State Highway 10 and got a ride from a guy in a truck. I understood nothing the man said. He didn’t take me very far and when I got off a farmer was standing near the road. He started to talk to me (People of rural Alabama very friendly). He had one of those Civil War accents, but I understood him well. He was a little put off when I told him that I was glad I understood. He laughed when I explained that I had understood nothing from the man who had just dropped me off. “Oh, that’s old Butch. He’s the town drunk. Ain’t nobody understands old Butch.”
Accents and languages can be fun. I am not very good at accents, but I did find an interesting performance by a woman who does 21 accents in a few minutes. She is at this link.