If you read my tweet below, you might be wondering whether my one year old daughter really said "Hi Dad" just now when I went in to give her a midnight bottle. Well, that depends on what you mean by "said".
Those were the sounds that came out of her mouth, but I can't vouch for intentionality.
The "Dad" thing is pretty common at this point. I'm Da, Dada, very occasionally Daddy, and sometimes Dad. Also sometimes Dadadadada if she's really pissed.
And she routinely calls for us by name when she wakes up in the night. She'll start with whichever of us put her to bed, and if that gets no response, she'll try the other one.
But the "Hi" thing is unprecedented. If it was real, she'll say it again. Real or not, though, it was totally heart melting.