I tink in a sense shadowing and singing might have lots of similarities. when we sing or shadow-speak "the song itself is usually pre-scripted" so we are singing "random lyrics" and not "our true opinions", we're not showing our true "self" identity. Singing also doesn't come with the expectation that someone will reply to your "opinion". Singing is also more for funzies rather than conversatoinal critique so there is less inclination towards self-surpression, no conversational turn-taking. there's no need to self-generate emotion and less ambiguity in intent. cultural and social norms on singing prioritizes forward flow of speech (so even if we make a small mistakes in "tone" or "we forgot a word in the lyrics" the expectation is to continue singing anyway. In contrast, in conversational speech "meaning/proposionality" is much more relevant resulting in "error-avoidance" mechanisms and resulting in inhibition (or suprression) of speech execution - being prioritized over the forward flow of speech). All in all, both shadowing and singing are basically associated with reduced evaluation of conditioned stimuli linked to "fear of social judgments", thereby lowering internal uncertainty i.e., inner conflict. But how do you look at it? Do you have another perspective on the matter?