Formal/Official:
* Address
* Broadcast
* Speech
* Public address
* Keynote
* Lecture
* Talk
Informal/Conversational:
* Chat
* Discussion
* Heart-to-heart
* Open forum
* Town hall meeting
* Informal gathering
* Casual conversation
Informal/Humorous:
* Snuggle session (if it's about intimate conversation)
* Cozy chat
* Fireside confab
* Campfire stories
Descriptive:
* Intimate conversation
* Informal discussion
* Direct address
* Personal communication
The best synonym to use depends on the specific situation and the tone you're trying to convey.