The paper provides an overview of the psycholinguistic studies of polycode texts which have been conducted in recent years at the Institute for Cognitive Studies at St. Petersburg State University. We describe the processing of different polycode texts by several categories of readers: native speakers of Russian, Russian teenagers, and students studying Russian as a foreign language. The eye-tracking technique is used for studying the reading mechanisms of verbal and nonverbal components of polycode texts. Text comprehension is evaluated by using traditional psycholinguistic methods (after-the-text questions, the technique of keyword set, semantic differential, and subjective assessment of text readability). The results made it possible to reveal the most easy-to-understand types of polycode text, offering teachers and compilers of modern textbooks specific methodological recommendations for selecting such texts and tasks for them.