I had a similar question a while back and ended up with Voip.ms.

https://discuss.tchncs.de/post/2418116

With projects like these, I’m always torn between thinking that it’s cool it’s possible, and horror that someone somewhere will try to use this in production code.

TIL. Thank you!

Depending on the complexity, there’s also abbrev-mode: https://www.gnu.org/software/emacs/manual/html_node/emacs/Abbrevs.html

I wish this was exaggerated, but it isn’t at all. Every time I try to learn Haskell, I end up in some tutorial: “You know how you sometimes need to represent eigenvectors in an n-dimensional plane with isotonically theoretical pulsarfunctions? Haskell types make that easy!”

Thanks! I found the instructions here, which don’t seem too hard: https://blog.voip.ms/voip-on-cell-phones-ios-and-android/

But otherwise, VoIP.ms looks pretty much like what I’m looking for. It also seems super super cheap for my needs (keep a phone number alive, make a few calls or SMSes per year).