An analysis of the state of pedagogical practice and scientific and methodological literature speaks of shortcomings in solving the problem of the formation of elementary schoolchildren's speech skills. This article is devoted to the formation of elementary schoolchildren's speech skills in interdisciplinary communication. The purpose of our experimental work is to verify the effectiveness of our methodology for the sustainable of speech skills in interdisciplinary communication. In preparation for the experimental work, the following objectives were set; to identify the level of formation of speech skills (motivational, informative, reflective), development of a complex of diagnostic methods: observation, questionnaires, diagnostic methods, assessment, self-esteem, etc., on the basis of the data obtained to determine the level of formation of speech skills in interdisciplinary ICT communication. Therefore, the aim of our study is to analyze the state of formation of elementary schoolchildren's speech skills in interdisciplinary communication. The theoretical significance of the study allows clarifying knowledge on the issue of the formation of speech skills; practical significance lies in the presentation and testing of a set of productive exercises aimed at developing learners' speech skills in interdisciplinary communication. According to the developed diagnostic technique, the formation of speech skills in interdisciplinary communication consists of three components: motivational, substantive and reflective. Based on these components, indicators and levels characterizing the formation of elementary schoolchildren's speech skills in interdisciplinary communication are distinguished. During the study, the results of a verifying, forming and control experiment were presented. According to the study, we can say that it is necessary to pay attention to the development of meaningful speech, because it is for this indicator that most children are at a low level of formation. On the whole, our study proved that systematic work is needed to form elementary schoolchildren's speech skills.