Abstract: The subject of the study is violations of the perception of oral and written speech presented during the instruction of the examinee and the presentation of stimuli of diagnostic techniques during the primary psychodiagnostics of candidates for service in the penal enforcement system and newly arrived convicts, suspects, accused, who lead to a decrease in the reliability of the psychodiagnostic information received about personal qualities and current psychoemotional state. The purpose of the study is to develop recommendations for the diagnosis of the quality of perception of oral and written speech in the framework of primary psychodiagnostics of candidates for service and newly arrived suspects, accused, convicted. Methods of theoretical and comparative analysis, generalization and systematization are used. The article presents the possible causes of the violations under consideration, systematizes the variants of their manifestations, provides recommendations on the organization and methodology of primary psychological diagnostics, which, subject to its further successful testing without the use of additional neuropsychological diagnostic techniques, reveals violations of oral and written speech perception and assesses the possibility of conducting reliable psychological diagnostics of personality traits and psycho-emotional states. The results of the study are intended for use by penitentiary psychologists, but can be used by psychologists-diagnosticians of any areas of practical activity. It is planned to further develop forms of diagnostic forms for conducting primary psychodiagnostics of service candidates and convicts, suspects, accused upon admission to institutions of the penitentiary system, testing and evaluation of their diagnostic capabilities.