Abstract
This article examines the degree and character of the interlingual interference influence on the understanding of new concepts and ideas by high school students enrolled in content and language integrated learning programmes. In this context, the main existing scientific views on the phenomenon of interlingual interference are analysed and compared with the views of 330 CLIL trainers from Central Kazakhstan, where more than 70% of high school students have been involved in CLIL programmes since 2018. The study contains an analysis of 385 written works and 74 video presentations of Russian-speaking high school students studying chemistry, biology, and physics in English as part of the model curriculum. The results allow us to conclude about the dual nature of interlingual interference in CLIL learning and develop effective techniques to minimize the negative impact of interlingual interference, which can be used further in the design and implementation of CLIL programmes.