I guess I’m going to be the voice of dissent, or at least clarification.
Babies *need *“babytalk”. That is, they respond more alertly and for a longer period of time to a high pitched tone with elongated vowels. The vowels are where it’s at for a baby; they’re what they learn to vocalize first. Most of us either sense this instinctively or are quickly conditioned by the baby’s actions into providing the kind of soothing, high-pitched coo they best hear and respond to. This doesn’t mean you’re limited to “Gooooo! Whoo’s a goooood babeeeee?”, but it does mean, as Sierra Indigo says, a lighter and friendlier *tone *than you’d use for your boss. I regularly narrate everything I’m doing or thinking or seeing to infants, but it’s definitely in a light and bubbly tone that I wouldn’t use with adults or older kids.
Toddlers are learning pronouns and possessives in particular, and the rules of conversation and polite phrasing as well. They need a lot of modeling for these. “I” and “you” are baffling (when you think about it, it’s really weird - if I say “here’s your towel,”, then you change that in your head to “here’s my towel,”, but if we’re talking about “his towel”, it doesn’t matter who says it. ) IME, they do best with a repetitive kind of talk so they can start to internalize the rules of grammar: “Oh, you found a hairbrush! Sally’s hairbrush! Your hairbrush! Let’s brush Sally’s hair. Let’s brush your hair…Now you brush my hair - brush Mama’s hair. Thank you! You’re Welcome!”
Preschoolers (and toddlers) need gentle correction, but not criticism. When they’re talking, the respond well to a lot of repeating what they say, ironing out any grammar errors without making a big deal about it. “Grandma gone to the stored!” “Oh, Grandma went to the store? What did she buy at the store?”
Once they’re around 4 or 5, then you’re into the territory Manda JO is speaking of. There’s always an element of “I’m in charge here, just in case the building starts burning down or something.” So while we can have conversations, they are never exactly the conversations of equals, in a power and responsibility sense. So just as I adopt a certain tone (of respect and deference) when speaking to my husband’s grandmother, I expect a certain tone (of “respect” - or at least lack of vulgarities and sass) from children. My tone to them is one of respect with a reserved right to correction or discipline.
Children are people. But they are not adults, neurologically, educationally or socially, and I don’t expect them to talk to me or me to talk to them the same way I talk to people who are my neurological, educational and social peers.