Wellington and Osborne explain that “The debate about language in science education goes back a long way. For brevity,” they continue, “we start in the 1970s [by citing Postman and Weingartner:]” (p.3)
“Almost all of what we customarily call ‘knowledge’ is language, which means that the key to understanding a subject is to understand its language. A discipline is a way of knowing, and whatever is known is inseparable from the symbols (mostly words) in which the knowing is codified. What is biology (for example) other than words? If all the words that biologists use were subtracted from the language, there would be no biology. Unless and until new words were invented. Then we would have a ‘new’ biology! What is history other than words? Or astronomy? Or physics? If you do not know the meanings of history words or astronomy words you do not know history or astronomy. This means, of course, that every teacher is a language teacher; teachers, quite literally, have little else to teach, but a way of talking and therefore seeing the world.” (Postman and Weingartner (1971), cited p.3 Wellington and Osborne)
Ref: (emphases in blue bold, mine) Jerry Wellington and Jonathan Osborne (2001) Language and Literacy in Science Education. Open University Press: Buckingham, Philadelphia.