Chimpanzees do not understand non-verbal communications even as much as dogs do.
You sure about that? I'm not a simianlogist but from what I've seen they seem to have very expressive faces and make use of posture quite a lot.
Or do you mean they can't read, which is hardly news. They don't write too well either.
These days, most American high school students can't read or write either. 'No Child Left Behind', my ass.