ASL/English Vocabulary in the Math Classroom

My last semester in college, while I was student teaching, I had a class that emphasized different key topics in the field of Deaf Education.  One such topic was vocabulary development.  We all already knew that students who are deaf/hard of hearing have a lower vocabulary than their same-age hearing peers for a variety of reasons not least of which being their limited access to "incidental learning" that comes from listening to other people's conversations/tv/radio, etc.  In our class, we talked about ways to introduce new vocabulary in order to give students a more connected understanding of the new word in its five distinct forms.

1. Picture
2. Description/definition
3. ASL sign (if applicable)
4. English word (in print)
5. Fingerspelling of English word

I try to be conscious of this as I teach.  It's very difficult sometimes, and many of the math terms to not have standard ASL signs, so it is more difficult for the students to attach meaning and use the new term through fingerspelling alone.

In Calc this week, I had my student doing practice AP Free Response questions.  One day, after completing a no-calculator free response question requiring justification of responses, I read the justification and was reminded of vocabulary difficulties.  The mathematical justification was great, but instead of saying the normal line is perpendicular to the tangent, therefore the slopes are opposite reciprocals, justification was that the slopes are "negatived and flipped."  In ASL, it would be an appropriate explanation, because the sign for flip and the sign for reciprocal are the same. This is the class that I have been most conscious about vocabulary! We have had English lessons in the middle of calc class in order to recognize the different forms of words that have the same sign.  i.e. differentiate (v.), derivative (n.), differentiable (adj.), derive (v.), etc.  The majority of the calc vocabulary (inflection point, slope, tangent and many others) does not have ASL signs, so we do a lot of fingerspelling with the support of written English on the board.  I am concerned that this might not be enough.

Any  thoughts on how to make vocabulary a more essential part of the curriculum or to get students actively using appropriate terms in writing?