The first speaker had a couple of vowels that gave away he isn't a native speaker, but he's walking the line between uncanny and mastery, so it was hard to pick out enough to guess what his native language might be.

The second I'm not allowed to watch without a Vimeo account, probably because I'm in Britain. I won't be setting one up today.

For the third there was a lot more unusual vowel articulation, especially 'a', that made me think Slavic, but I couldn't be any more specific than that.