I think it's more likely that a lot of people just happen to be insecure, without any causal relation to mirroring. Sharing inflection, accent, and mannerisms

I think it's more likely that a lot of people just happen to be insecure, without any causal relation to mirroring. Sharing inflection, accent, and mannerisms yields a wealth of context that aids both the listener and the speaker in acquiring detailed insight about one another's culture, language, and meaning. I suspect that people who don't mirror might sadly be unaware of these subtle but rich details, even in their own communication.