General:
* Having a chat
* Engaging in conversation
* Exchanging words
* Communicating
* Speaking (this is a bit more formal)
* Having a dialogue (implies a more structured discussion)
Informal:
* Shooting the breeze
* Catching up
* Having a chinwag
* Spilling the tea (used in slang, often about gossip)
Formal:
* Discussing
* Debating
* Conversing
* Interacting
More creative:
* Spreading the word
* Sharing thoughts
* Vocalizing
* Expressing oneself
The best euphemism will depend on the specific situation and the tone you want to convey.