Analysis of optimal conditions for the exchange of objective information is concluded in the principle of word-sign signalling. The principle assumes analytical fragmentation of reality into particular features and relations. Correspondingly primary stage in child's mastering of language is regarded as a period of extensive fragmentation of perceptual images with further linking of the fragments with different words; this stage is therefore also a period of development of the ability to integrate corresponding elements into the acts of judgement. The position presented in the paper is considered against theoretical views of B. W. F. Gegel, A. Potebnya, I. M. Sechenov, I. P. Pavlov, K. Goldstein, and some contemporary theories concerning the role of the word in mental development.