I know it sounds weird, but this is what my lo is doing. When he talks to me his mouth is closed and he will hum. But it’s like humming words because he pauses in between and his pitch get high and then low. He can say mama, dada, & bubba but not directly to us. It’s more just babbling it while playing. He can sign more, please, milk, all done, & thank you. He also can point out his body parts when we ask him. He will be 18 months next month. I plan on discussing this with his doctor at his 18 month check up, but was wondering if any others do this as well.