I'm an English folk musician and it's perhaps surprising to many people, considering the prevalence of English and our modern music, that we as a country have lost a huge amount of our songs and music over the years. We have however re-entered a folk revival since the 70s and it has combined with the national pastime of peculiar hobbiests having documented a lot of really obscure things.

But anyway, my partner sings one of our oldest documented songs, which I would classify as fairly unknown outside of historical circles and in an older form of English that is quite tricky to decipher: https://m.youtube.com/watch?v=Kr2LRpx4Uyk

I learn quite a few tunes and songs from various countries and it's interesting as to which I find immediately feel familiar to me. Scandinavian, French, Belgian, Breton, Quebecois stuff etc is very popular in folk circles here in the UK and I both listen and play a lot of it. Though a lot of us might struggle to sing along you might be surprised at how far some traditional songs travel :D