I have real problems pronouncing a couple sounds here. Ryu, for example. It means "dragon." The problem is, when someone says these words, they sound like a combination of "L" and "D" to me, and not "R" at all!
Kudasai (thank you), the same sort of thing; it sounds like "kurasai" to me. It's like I hear the opposite of what's transliterated, or something. If I can get someone to say the word for me several times, I can usually get the sound, sort of. The thing is, D is in the front of my mouth, and R is in the back, so they shouldn't sound alike at all, right?