To me, the funniest mispronounced Japanese word by Americans is hara kiri. Americans pronounce it "hairy-carry". And it's actually extremely difficult to write out how it should sound phonetically, but it's more like hah-rhah kee-rhee". Though even that's incorrect. There are no true "R" sounds in Japanese, and what I wrote as "RH" is kind of a quick, rolling sound that's impossible to precisely capture phonetically in English.
Jim
Jim