[Paul11]

I knew people who graduated with four-year degrees in English and couldn't string together a sentance. At least three times I met groups of men where one was a school English teacher who pretended to be asleep to avoid showing his lack of English.

As far as learning Japanese, the grammer is pretty easy. The difficult thing for some people is the accent. Beyond that, some people learn the language but don't bother to learn the cues, aizuchi o utsu, sub-lingual communication and some psychology that makes communication more efficient.