Marykriss,I'll send you more info to your private e-mail but:
--the TDD is available through the California Relay Service (since you live in California). Per Federal Law, these services are available to people who need them for *free.* Other states have their own programs. The three people with SD (Californians) I know who use the TDD swear by it. It depends on your circumstances. Also, your breathing difficulties may be an issue (either help or hurt use of the TDD...hard to say). Give it a try...you can't lose a dime.
--ASL (American Sign Language) is taught at most community colleges, as I'm sure you know...since you're back in college. I took two semesters of it many years ago when I was trying to communicate with a deaf woman who worked in our office. Like any language, it takes alot of training over time to really learn it. Two semesters only taught me the very basics. I have lost my skill but plan on taking it up again. What that will do though is ensure I (you) can communicate in the deaf-community. Just because you know how to sign doesn't mean others will understand you as they would have to know how to sign also. If you're using a chalk board to communicate, learning how to sign will give you more power and open some doors. More info coming off this BB.
Good luck with both of these issues,
--Lynne