Analysis of the data obtained in studies of acquisition by children of grammar and phonetics shows that there exists a biological program behind the process. The code of the latter differs from that of the social program: its units are triplet and not binary. Elements of the triplet set are hierarchically organized: two of them are products of the dichotomic split of the third one. In their turn they may give rise to another two by the same splitting mechanism in the process of further development. Consequently there appears a characteristic hierarchy in the form of a dichotomy or a tree. While relations between elements of the social program are of the "or - or" type, here we have relations of the "and - and" type. The biological program unfolds not from the particular to the general, as is the ease with the social program, but in the opposite direction from the general to the particular.