I like the word "assimilate" in some ways, [MENTION=24208]Spoonman[/MENTION], and think it's pretty appropriate here. In order to really hone-up on the German language, I took the advice of a good friend and mentor, who recommended that in my first two years, I first establish a circle of German friends and talk with them only in German, cost what it will, and since I do lots of sports, that was easy to do. He also recommended that I buy books that I had already read in English and this time, read them in German. So, I started with Frank Herbert's DUNE trilogy. He then recommended that when I watch TV, only Station 1 (ARD) and Station 2 (ZDF), because the reporters speak perfect High German (Hochdeutsch) - without accent. Of course, everyone has an accent of sorts, but the concensus is that the cleanest of High German comes from the city of Hannover, so it is called "hannoverisches Deutsch". So, yeah, the assimilation thing happens with time, but I am still through and through a US-American and proud of it.
After being here so long, I note even the slight changes in body language and clothing that separates Americans from Germans. Just yesterday, when I was with my little one at a fete (with lots of jarring rides, cotton candy, the works), as we walked by a couple with two kids, based on how the guy was walking and wearing his jeans, I know he was an "Ami" (the German slang for "US-American") and sure enough as we passed that couple, he was speaking English with a midwestern Accent. I said a quick hi to him and his wife, it ends up they are from Auburn Hills, Michigan (suburb of Detroit) and he studied at the University of Akron, which is one of my two Alma Maters. Small world. Chuckle, chuckle.
Now, if I catch a film in English late in the evening, a strange thing often happens: in my dream, I rerun part of the film, but in German, in spite of the fact that I just saw the film in English. The human brain is an amazing thing.
So, yeah, "assimilated" is pretty accurate.