The basic fact we encounter in a genetic analysis of the relationship between thinking and speech is that this relationship is not constant. The quantitative and qualitative significance of this relationship changes in the course of the development of thinking and speech [9] . These functions do not develop in parallel, nor is their relationship constant. The curves that represent their development converge, diverge, and cross one another. At one point in the process, these curves may move smoothly along a parallel course, even merging with one another. At another, they may branch away from each other once again. This is true of the development of speech and thinking in both phylogenesis and ontogenesis.