From delay of speech development to deviations in possession of speech in logopedic practice

The article summarizes the interdisciplinary analysis of the essence of the speech therapy conclusion and the medical diagnosis of “delayed speech development” in the historical aspect. Based on the methodological concept of the cultural-historical origin of higher mental functions, in particular speech, L.S. Vygotsky determined the fundamental requirements for the formulation of “pedagogical diagnosis.” As a result of the synthesis of our own empirical base for studying various types of speech development of more than 1,500 infants and young children in the model of communicative speech development from birth to the first phrase, we derive the logopedic conclusion “deviations in mastering speech”. The logopedic conclusion “deviations in the mastery of speech” is a logical continuation and development of the essence of the logopedic conclusion “delay in speech development” in the modern space of empirically accumulated data and their theoretical generalization.