My son and friends went to Iceland and hike a few trails and camped out there. He noted that when a group of Europeans passed, they remained silent and only glanced up when greeted with an American "Hello", but otherwise, remained silent.
I'm new to sailing (one year in), but I've traveled extensively around the world (every country in Central American and 8 of 12 in South America). I've also traveled all over Japan, every country in Western Europe, and a significant part of Eastern Europe. I've spent the past 7 years working in Norway, Sweden, Denmark, The Netherlands and frequently layover in Iceland to tool about for a week or so.
I think a lot of Americans misidentify what they experience in big cities (like Paris) as a representation for the whole country. One would certainly not expect the sometimes brisk nature of someone in NYC to represent the warmth and etiquette for the rest of the US. Likewise, people in Paris can often be in a hurry and a bit curt, but when you travel anywhere outside of Paris you'll find people as warm and loving as any small town.
I'm most familiar with the culture in the Scandinavian countries and Iceland since I've worked there for so long and it is definitely true that specifically in Norway and Iceland they do not speak to *anyone* they don't know unless spoken to first. They speak better English than many Americans, it is definitely not a language barrier. In their culture, it is a "respect of privacy". You might be deep in a thought , or busy, or in a hurry to be somewhere and engaging a you in unnecessary conversation is seen as a rude invasion of privacy.
The oddest place to experience this for me is always in a pub, but if you speak to them, they'll most certainly be warm and embracing and speak to you. (And this was in English. I only learned Norwegian two years ago.)