I find Japanese pronunciation to be straightforward and easy. But, for some reason, many people murder Japanese words borrowed into English. Take "karaoke", for example. I hear Americans pronouncing it as something like "carry Okie". How did that get started? You can listen to the Japanese pronunciation here. Cf. the UK and US pronunciations here.
On "sudoku", Bean remarks:
Today during a scientific talk, I heard yet another well-educated (English) speaker stumble over the word "sudoku". It came out something like sah-doo-koh. This happens all the time, and people somehow know it's wrong and hesitate but can't choke out the "proper" pronunciation. Why? What's so special about that pattern of sounds that makes it so hard for English speakers?
I actually hear more Americans approximating the Japanese sound of "sudoku" than they do for "karaoke". But I wonder how many different ways there are to pronounce "sudoku" in English. Even before Bean wrote in with her questions about the English pronunciation of "sudoku", I often pondered how the passengers on the commuter trains I ride, many of whom are absorbed in these puzzles, pronounce the word to their friends and in their own minds.
For those who are interested in etymology, "sudoku" literally means su ("number") + doku ("single").