The article addresses psycholinguistic preconditions for development of the communicative component of speech activity in 5-year-olds with general speech retardation (GSR). The development of speech activity is analyzed through the lens of psycholinguistic motivation for the emergence of speech units. The authors for the first time identified psychological mechanisms that underlie disorders in the development of the communication component of speech activity in 5-year-olds with GSR and suggested effective interventions. The research involved a study of probability prediction within the structure of the communicative component of speech activity of 5-year-olds with GSR. The author-developed classification of non-verbal and verbal probability prediction formed the basis for a theory-based diagnostic tool to assess the communicative component of speech activity in 5-year-olds with GSR. The research demonstrated the importance of probability prediction as a dynamic process and indicator of practical realization of utterance and holistically developed coherent speech. The analysis of disorders in cognitive and speech operations and functions identified in the study points to the dominant role of weak probability prediction function at non-verbal and verbal levels. Weak probability prediction was defined as the cause of poorly developed communication component of speech activity in 5-year-olds with GSR.