"See You Later"

My daughter's vocabulary has been quite outstanding for months now. She's saying more phrases instead of just one word like "good girl," "where's _____," "there she/he is," "I want _______," "baby Einstein," "bless you (when someone sneezes)" and many more. But yesterday I was completely surprised when she told her Dada "see you later" when he was about to go to work. When I heard her say it, I froze for few seconds, just stunned of this new sentence added in her ever-growing vocabulary. We taught her most of the phrases and words that she has learned by now, but "see you later" wasn't. It's something she learned just from listening. I just realized that I always tell my husband "see you later" when he's about to go to work on weekdays. That's where she got it—from me. I remember on her 18-month wellness check-up, her pediatrician admonished us to watch what comes out from our mouth (words) because she's already in the stage where she imitates what she hears or sees. Kind of the saying "monkey see, monkey do" or let's say "monkey hear, monkey say."