[OP Jason White against branch https://github.com/w3c/apa/tree/RTCUserNeeds]

There’s an enormous difference between an incoming text string and an outgoing text string in terms of how each is processed, so the system can easily distinguish the two. It isn’t clear at all what is being sought here. Ensuring that the UI doesn’t intermix incoming and outgoing text would obviously be essential – but that’s true for all users, not just those with disabilities. Can you formulate the UI requirement more clearly?