I found an app called Voice Dream Writer. Based on Dena's advice about needing a pad to write on combined with my difficulty writing, I went out and bought an older model iPad Mini. I installed Voice Dream Writer on it, and turned the font size way up. It looks like with this app, I can type messages in really big letters and then have it read them out loud if I need it to. It's a little bit like a notebook and a speaking assistant rolled into one tool. As far as I can tell, I can write out parts of predictable conversations (like when I'm ordering food I order often), then pause between fragments of text in order to respond to the other person as they talk. I don't know if that's going to work in practice, but it seems like a good place to start.
Dena, did you find that you needed help going to the bathroom early on? I had that problem with FFS, but I was assuming that since I'm allowed to go to the hotel after surgery, I might be in good enough shape that I could shamble into the bathroom myself.