It's not that we are not familiar with pedagogy, it is just usually kept to technical, professional contexts and not much used in every day contexts. It is only a matter of conventional that we call what we study as teacher "education" rather than "pedagogy".
Not to be pedagogical, but linguistics is the study of language in general. If you are studying individual languages (in order to teach them or study their literature for example), then you are not studying linguistics.
We don't use pedagogy much in American English. I suspect it's due to the negative meaning of pedagogue (dictionary.com) : 2. a person who is pedantic, dogmatic, and formal.