did you know?
There are many clients than support adding encryption layers to your favourite generally plaintext communication protocols!

Try email with PGP (I like k9 and claws-mail),
XMPP (jabber, what Google Hangouts uses) with OTR (pidgin) or OMEMO (XMPP/Conversations-- OMEMO is the same protocol Signal uses!)
or Riot (a matrix client) for IRC!
(note that this last example is a bit silly, as once you have Riot set up you can just use Matrix, and everyone on the channel also -needs- Riot.)