This paper addresses the code-switching phenomena in contemporary Karelian speech (Livvi dialect), focusing on their structural, morphophonological, and pragmatic aspects. While Karelian-Russian bilingualism has been widely studied, a range of key problems regarding code-switching patterns, mechanisms of morphophonological adaptation of donor-code elements, and their communicative functions remain understudied. This study addresses this gap by providing a formal analysis of Karelian-Russian code-switching. For this research, a corpus of 41 recordings (3.6 hours) of spontaneous narratives collected by the authors in 2024–2025 is used. The analysis follows Johanson's and Muysken's theoretical frameworks, employing formal analysis of the distribution of discursive context types, morphophonological models of embedding the elements of the donor code and their part-of-speech features. The results showed that code-switching occurs in 65% of utterances, with insertion as the dominant strategy; nouns show the highest frequency, exhibiting extensive global copying; verbs and adjectives demonstrate stronger morphological adaptation; switching peaks in metatextual discourse types (comments, quotations). The results confirm the systematic nature of Karelian-Russian code-switching, while suggesting need for broader investigation. The study contributes to contact linguistics by examining code-switching patterns in dominant-language bilingualism contexts.