Does Cadence support multiple languages?

Yes. Cadence does accept use of multiple languages and special characters/symbols.

For outgoing messages--Cadence generally stores/transmits in unicode, which covers just about every character, however, there may be some characters that Twilio (SMS Gateway Provider) changes.

Within Cadence, there isn't a symbol library, however, use of keyboard shortcuts, alt codes, and/or paste in those characters into a message.

Note: Smart Messages do not currently support yes/no responses in other languages. 

Incoming messages-Characters/symbols for other languages are not restricted for incoming messages, however, there may be times where carriers/handsets alter a character before it gets to us and we wouldn't know.

Opt out/in keywords must be in English for a successful opt out.