It's funny that you should mention that because I just got back from a grocery trip with K where we got lots of "that's so cute!" looks. K and I sang Raffi songs through the whole store while adding extra verses.
I've always talked to K. I'd like to say it was a conscious choice in order to develop her vocabulary but it's probably just because it's more socially acceptable to talk to your baby/toddler than to yourself. Especially in stressful situations (like trips to the grocery store), talking to myself outloud can really help with my anxiety. So instead of whispering my inner monologue, I can just say it louder but to my kid. Kids are actually a great coping tool for anxiety. Like when you're at a party and you don't know what to talk about, you can talk about your kid. Or you're uncomfortable with a situation but don't know how to leave- the baby needs a nap. Maybe doctors should start to prescribe procreation for social anxiety?
Your anxious sister,