My husband and I talked to our son a lot when he was a baby. (For the record, we talk to him a lot now, too, but we are not sure he is always listening.) We talked in a slightly higher-pitched tone, with big smiles on our faces and short sentences. He liked it then (but probably doesn't now.)
We were super excited in those early days of baby babble, when he started mimicking our sounds. Sure, a lot of the time he screeched like a baby pterodactyl, but it wasn't long before he said his first word. (For the record, it was "mama." Well done, little man.)
It wasn't until my son was older and I started reading more parenting research that I learned we were speaking "Parentese" and how important it is to a baby's development. Babies need to hear us talking in those higher pitches constantly so they can figure out how the whole language thing works. And this eventually makes them better talkers as they get older.
I'm wondering if this inclination is semi-instinctual. We did this without even thinking about it or making a game plan or critiquing each other's pitch. I don't recall anyone ever telling me, "Talk to the baby all the time." Maybe it's one of those things I picked up on other parents doing without ever noticing.
Anyway, it works and it helps build vocabulary, and even though it feels silly at first you get used to it over time. Just be sure to use your normal tone when you speak to adults again.
Did you make an extra effort to speak to your baby all the time? Tell me about it in the comments.