On the 9th of March, 1989, F. A. Sokhin, well-known soviet psychologist, died. To perpetuate the memory of F. A. Sokhin, part of his unpublished thesis for a Doctor's degree is presented. Language mastering by a child is characterized not only by imitation of adult's speech and intuitive adoption of language means and norms, but first and foremost by development of language generalization and elementary realization of language phenomena.