

If you don’t need voice, there are a lot of options. Matrix has IRC support and encryption, and has voice options if you self host.
Riot is… A Discord clone without working voice and I found it to be an odd duck.
There’s RocketChat… More Slack like.
Mattermost.
I replaced my voice/video chats with Nextcloud Talk and/or Steam, based on the scenario. Outside of those, Matrix is good for community needs in my mind.






And to be fair, nothing in the question specifies the language to continue the conversation in.
Sure it’s ESL class, but within the context of this question… No rules were broken.