Every subject has content-specific vocabulary associated with it. Examples from Language Arts include literary devices such as “simile” and “personification.” In Social Studies, forms of government such as “monarchy.” In Physics, “photons.” And in Math, “numerator.”
Being proficient in an academic subject thus requires being fluent in its language. And the best way to achieve such fluency is the same as it is for a foreign language: immersion—being placed in an environment where that language is spoken routinely. Your classroom must therefore be such an environment for your students, which means resisting the temptation to water down language just because students may struggle with it. What you need to do instead is adopt a “define a term once, use it always” approach. No more asking students to choose a different “word,” but rather a different “preposition” or “adjective.” No calling it “water,” but rather a “lake” or “river” or “ocean.” No using “category” when you really mean “phylum.” And no reverting to “answer” rather than “sum” or “difference” or “product” or “quotient.” (And Algebra teachers, can we do away with “the number in front of the letter” once and for all?!)
A key, of course, to students becoming fluent in the language of a given subject isn’t just you talking the talk, but insisting they do so too. It’s important, therefore, to provide students resources for looking up terms they’ve forgotten. You then need to create activities that regularly engage students in using those resources. A couple of my favorites: open-note quizzes/tests, and using previously defined vocabulary to define a new term without giving the name of that new term (eg., “a quadrilateral that is equilateral and equiangular” required students to look up as many as three words, only to then realize I had just defined a word they’d known since pre-school: square).