Introduction. Cochlear implantation (CI) is the most effective way of rehabilitation for children with profound hearing loss. Choosing the settings of the CI processor is an important task, because the child’s speech intelligibility and understanding depend on the parameters of processor stimulation, and, consequently, the subsequent auditory-speech development and integration of the child into society. Аim. To evaluate auditory and speech development in a group of children aged from 3 to 14 years using different CI systems: Medel, Advanced Bionics, Cochlear, Nurotron, Oticon and Neurelec by using the MUSS Scale (Meaningful Use of Speech Scale) and the method of speech audiometry in a free field sound. Materials and methods. The study includes 82 children with CI. The children received complaints, medical history, examination of ENT organs, consultation with a surdo teacher, setting of the CI processor, assessment of speech intelligibility by using speech audiometry in a free field (n = 82) during the process of setting the CI processor and after setting. In a group of 56 children (n = 56) of preschool age from 5 to 7 years, parents answered the questions by using the MUSS Scale (Meaningful Use of Speech Scale). Results. According to speech audiometry data, the intelligibility of monosyllabic words in the free field was 70.85 ± 1.44%, and of multisyllabic words – 74.51 ± 1.60%. The results of speech intelligibility after setting the CI processor significantly improved and amounted to: monosyllabic words – 76.95 ± 1.31% (p < 0.01), and multisyllabic words – 83.78 ± 1.43% (p < 0.001). Conclusion. The Scale of Meaningful Speech Use (MUSS) is a simple tool for assessing the development of speech in cochlear implanted preschool children. Speech audiometry in a free field can be used to assess the level of speech intelligibility and to determine the parameters of speech processor stimulation. © 2025 Elsevier B.V., All rights reserved.