When Italians speak Russian, do they think in Italian or Russian? Or does the thinking not happen in either language? This work is an attempt to answer these questions by an experimental piece of research. The speed and success of the acquisition of the syntactic hierarchization and discourse structuring in Italian native speakers learning Russian L2 were measured and matched in order to compare the distances between Italian and Russian on these two levels. It was demonstrated that the way the speaker uses a linguistic system is not a totally free and arbitrary choice, but it follows certain regularities, and constitutes his textual-discourse competence, i.e. the language use is specifically structured, and the native structure of the linguistic use is much more resistant to the acquisition of the second language than the morpho-syntactic component, probably because the former influences the speaker’s thinking.