Yup. There's the separation between language fluency as well. BICS (basic interpersonal communication skills) can form within a year, and make people seem fluent or even native-like. CALP (Cognitive Academic Language Proficiency) however, will take as much as 10 or more years to form. So academic language takes time, yo. Which is why education is so important. Because if you can't develop CALP, or aren't given enough time to develop it *cough* NCLB *cough* you're cutting people off from a lot of things.