The current importance of the topic under study stems from the role of international treaties that establish security and protection of human rights. Moreover, within the UNO agenda 2030 for sustainable development, child rights are central. Thus, the task of quality translation comes to the forefront in multilingual communication that is often affected by language interference. The linguistic relevance of the research is supported by the fact that the works looking at interference of foreign language into native language in translation of legal domain are practically nonexistent. Due to the above, the paper aims at investigating this phenomenon in legal discourse on child rights. The leading approach to the study rests on the qualitative methodology and combines theoretical and empirical investigation. The latter integrates contextual analysis, comparative and contrastive methods allowing to identify the channels and nature of language transfer. A statistical method of analysis contributes to the quantitative assessment of interference. The research materials include the English and Russian versions of the Council of Europe Convention on Protection of Children against Sexual Exploitation and Sexual Abuse. The choice is determined by the fact that it is one of the major documents on child rights protection that has not been subject to language or translation analysis so far. The research findings describe channels and types of errors provoked by interference in multilingual communication on child rights. The results provide instruments to predict and avoid such errors in the course of drafting multilingual legislation and its interpretation within domestic language legal culture. © 2019, Slovenska Vzdelavacia Obstaravacia. All rights reserved.