Most infants are babbling well before twelve months though. In fact, you will usually hear your baby's first words, which are usually mama or dada, by the time she is six to nine months old. Your baby won't use those words more specifically or correctly until she is seven to 13 months old though.
Sources:
Functional developmental evaluation. Prerequisite to habilitation. Capute AJ - Pediatr Clin North Am - 01-FEB-1973; 20(1): 3-26
Linguistic and auditory milestones during the first two years of life: a language inventory for the practitioner. Capute AJ - Clin Pediatr (Phila) - 01-NOV-1978; 17(11): 847-53
Clinical linguistic and auditory milestone scale: prediction of cognition in infancy. Capute AJ - Dev Med Child Neurol - 01-DEC-1986; 28(6): 762-71
The Denver Developmental Assessment (Denver II)
