Speech is an optimal human communication, formed by the rhythm of sentences, words and slogans. Speech development is a complex process, and when it does not go foreseen, but slow, discontinued or defective, it is called a slowed linguistic-speech development. An important role in identifying these difficulties are both family and educators, who are most often the first to notice. Assistive communication, or alternative or augmentative communication (AAK) uses alternative means or enhances existing ones and is intended for people with complex communication problems and those who have difficulties using and understanding language and speech. One of assistive communication methods is neurofeedback. This kind of approach is a direct training of brain functions by which the brain learns ways for better and more efficient action and work. Presented in this paper is the influence of assistive communication, neurofeedback therapy, on the slowed speech and language development of a preschool child. The case study of the influence of neurofeedback (EEG biofeedback) on the slow speech development in a boy with neurorisks is described. Using the methods of documentary tracking and interviewing a preschool teacher and a neurofeedback expert, the results of many years of work are presented, along with the unimaginable impact of this type of therapy on the overall development, as well as the behavior and personality of a child with slowed speech development.