i am not a native speaker in american, and i notice that every day... funny, i have always worked in international labs; english was the everyday language and talking about my work is difficult for me in dutch (some words dont even exist in dutch). but only here in the US i realized that my english is not that good (my excuse for everything nowadays! useful!); we all spoke english as a second language, and i guess that is why we never had a problem, we were all as limited; the pace was a little slower when speaking. now it sometimes goes soo fast for me! on top of that, often americans mumble, and i just have no clue what they are saying... ( i do not at all like to call, call centers are the worst).
there are also a lot of expressions and words i never heard of ("wicked funny", "im sweating my balls off" (for guys, i believe.. ;), "anomaly"). and i still have trouble with "hey, how are you?" or "whats up?" when just walking past someone in the hallway. i always think i have to answer this question..... then there are expressions i am now familiar with, but cannot get myself to use, as i think everyone immediately will notice i am not an american! like "like", or when giving directions: "you hang a left after you turned right". going out to dinner: "yes, we are all set" or "no, we are still picking away on this". when saying bye "have a good one". i could go on, if only my english was not so limited... ;) ah, and "awesome" of course...
the very first time i entered the US and was questioned by a bored officer i could not understand one of his questions, no matter how hard i tried. i asked him 3 times to repeat his question, and got so embarrassed that in the end i just answered "yes". but what he then said i did understand; "to this question you should have answered NO!" however, i still do not know what the hell he asked me!!
(i know i told this story already a million times, by now having i written down here, i will stop telling it... :) )