PenPal World - Connect with people all over the world

Chatib - Chatib is an online chat room where you can meet and chat with new people, make them friends, or even data them online.

InterPals - InterPals is a friendly community of over 5 million friends, language learners, travelers and penpals.

ChatSecure - ChatSecure is a free and open source messaging app that features OTR encryption over XMPP.

Polyglot Club - Polyglot Club is a new social network for language learners.

Element.io - Secure messaging app with strong end-to-end encryption, advanced group chat privacy settings, secure video calls for teams, encrypted communication using Matrix open network. Riot.im is now Element.