A study of the babbling and phonological development of 54 infants used half-hour videotape recordings of the children at play in their own homes. The vocal output was phonetically transcribed twice for interrater agreement, and analyzed for the consonants used five times or more in the child's vocal repertoire. These consonants were considered to be in the subject's voluntary control. The controlled phones were rank-ordered for their frequency by age, and the mean numbers of phones for each age were computed. For the group as a whole, the most frequently controlled phones were /d/ and /h/, occurring in about two-thirds of the subjects. The second most frequently controlled consonants were /m/, /b/, and /g/, occurring in 41-44% of the subjects. The last group of segments with notable frequency included /n/, /w/, and /j/, occurring in about a third of the subjects. The remainder of the consonants showed sporadic or near zero occurrence. No sex differences were found in the data. The major trend observed was consistency in the place and voicing features of articulation in the first consonants exhibited in the age range. However, there were individual differences in the selection of which voiced front sound characteristics were used and broad differences in the manner of production. Less consistency is apparent in the choice of low frequency consonants. Substantial consistency with the results of previous research was found. (MSE)