Everywhere I read, baby babbles from 4-6 months forward. My daughter is 6 months and 1 week old and she still does only aah. She squeals and makes noises but still no da da or ba ba.. We all talk to her a lot. My mom,dad DH and me. We read to her and sing to her but she still only does aah. Should I be worried? Also do babies babble all day long? Or on and off?