Thanks everyone for the feedback on your own experiences! For those who can process simultaneous conversations--or those whose children can--how did you navigate the social implications? At what age did theory of mind around this ability begin to emerge? As of yet, DS seems to believe everyone can process two overlapping conversations.
When he talks while we read or watch a video, which he does about 20% of the time, I just keep going as long as he shows interest. I'm also starting to enforce a one conversation at a time rule to teach proper manners at other times. Let's face it, unless your interlocutor shares your ability, talking over someone is bloody rude, and it will be most painless for him to learn that lesson early.
