Just a little concerned...

My daughter is 8 1/2 months old, and has so far reached all her milestones except for one. She hasnt started that babbled baby talk stuff. I remember my oldest doing it at like 4-5 months and on. But my youngest just doesnt try. She will make noise and laugh and go "ahhhhhhhhh" but thats it! I hope she starts soon! I know her hearing is good because she knows her name and looks at us when we make noise or call her name. Anyway, she has a doctor appointment on April 20th to start catching her up on her shots since she hasnt had any since she was one month old.