This article reports the analysis of the cross-linguistic influence in the intonation of the Russian and Brazilian Portuguese languages. Recordings of the Russian speech of Russophones living in Brazil were used as the material for the study. The paper demonstrates that in their speech, when implementing the third intonation construction (Bryzgunova's classification), the melodic peak shifts to the left, closer to the initial border of the stressed vowel. A perceptual experiment involving native Russian speakers shows that the presence of the peak shift to the left significantly affects the perception of intonation as unnatural.