A lot happens around the half-year mark. "Between four and six months of age, the baby is smiling, giggling, and very fun to have around," Dr. Jacobson promised. "By six months of age, the baby gets better at rolling and sitting. The baby will stay up for a few seconds when placed in a sitting position but cannot sit up by herself." In addition, she said, "the baby starts to add consonants into the vocalization such as bababa, dadada, gagaga — M sounds are a little harder so they do not usually say mamama at this age. The baby also can move things from hand to hand and have good grasp so they pull hair very well." Watch out, mom.