Background: The present study reports preliminary results from the multicentre project on the approbation of the Russian language version of the “The Communication Checklist-Self Report” (RL-CC-SR) and its first use in schizophrenia (SZ), aiming to evaluate the contribution of language disturbances in the pathogenesis of this heterogeneous disorder. Subjects and methods: The study evaluated patients' clinical state with the Diagnostic Interview for Psychoses (DIP), and assessed language and communication disturbances (LCD) with the RL-CC-SR in all participants (213 healthy controls (HC), 83 SZ patients, 31 SZ first-degree relatives). Data from the current sample of SZ (n=50), and HC (n=213) was analysed to calculate the relationships between LCD, social and clinical variables using descriptive statistics methods, T-test and Pearson's correlations (SPSS-26, 2019). Results: The quotient scores (<6) and raw scores on all three CC-SR subscales demonstrated prominent LCD in SZ: (i) language structure (LS) (SZ:11.92±8.01, HC:7.54±5.91; p<0.001), (ii) pragmatic skills (PS) (SZ:11.30±10.07, HC:8.71±7.39; p=0.040), (iii) social engagement (SE) (SZ:31.94±11.76, HC:19.42±10.35; p<0.001). In SZ, Pearson correlations of LS scores were significant for the DIP-items Odd Speech (p=0.033), and Social Engagement - Blunted Affect (p=0.042). PS was related to early disease onset (p=0.027), poor premorbid work adjustment (p=0.003), along with LS (p=0.005), and was also linked to poor premorbid social adjustment (p=0.005). Conclusions: SZ patients are aware of their LCD at all levels of language structure, pragmatics, and nonverbal communication, but are unable to compensate. Disturbances of LS and PS in SZ patients relate to their poor social adjustment and functioning, and may prove to be associated with the primary negative symptoms domain of the disorder and its generally poor outcome.