...as many Americans tend to sound with foreign languages since American english is not phonetic like Japanese...
OT post: I agree with one point that most Americans really sound awkward when trying to speak another foreign language, particularly languages from Asia. However, all languages are inherently phonetic (even sign language, which has its own sets of phonemes / phonetic articulations), because the signs have to be articulated. I might have misread your post, but I would probably point out the cause of this awkwardness to the difference between the phonological systems of the languages you mentioned.
Hope you don't take this point of information as being confrontational (as most guys here would) from someone who makes a living out of language teaching.