Separated by a Common Language has written an intriguing post about the ways that Americans and the British talk about class– or, to be more accurate, about how Americans talk about occupation (“blue collar”, “white collar”) while the British talk about class.
Phrasing class-talk in terms of job types or income sits well with the American discomfort with class-differentiation. Putting people into classes seems like it’s defining who they are, whereas defining them in terms of job describes what they do and defining them in terms of income is by what they are getting. Doing and getting are activities, and activities are changeable. Being is a state, and more time-stable (a term from linguist Talmy Givón), and therefore perceived as less inherently changeable. If you’re uncomfortable with describing someone as being something, a solution is to describe them as doing something or having something done to them. This fits with the American notion of equality of opportunity.
And thus, the enormous challenges of doing anything about class, when we cannot even speak of it.
Education and Class 
I also think it’s hard to talk about class because most people, no matter their actual class status and their “collar,” think of themselves as middle class.
Hello Jeanne,
That’s really true. I’m teaching a class on class now, and the students — all seniors or grad students — are somewhat stunned to realize that this is the first time in their formal education that they’ve ever talked about any of this. They’re educators or educator wanna bes, charged with leveling playing fields through formal schooling, and they’ve essentially had nothing to tell kids beyond “work hard and you’ll make it”, even while any of number of them were uneasy with that.
So there’s the popular perception, and then there’s the silence in education (at least outside sociology courses in stratification, maybe) that leaves those assumptions in place.
At least in Great Britain they can talk about it.