Hey Alpaca,
I'm happy to hear that your lump doesn't seem to be problematic any more. I also am a teacher and I am also currently teaching myself how to speak more clearly and effectively. My speech therapist sent me a gazzilion tongue twisters and told me to call her if I needed anything else, so I have been talking to a school speech therapist in my building. She mentioned putting a long wet frozen q-tip on the middle of the tongue to create a hollow there. She said that would improve the s sound and it does, to some degree. It takes a few weeks of once a day for about 10 minutes to see results. Good luck. Let me know if that helps.

I also love the Spanish lisp idea. I teach in an international school and will have to use that one. I also will use my tape recorder. So far, only one student has asked me what is wrong with my speech. It's a new teaching job for me, so they never heard me before the surgery. And only one student has noticed and commented on my neck scar. Funny how you think these things are more noticeable than others do.