The paper describes the first stage of a study of multiword units in the mental lexicon of
a Russian speaker. Based on the guides on Russian spelling and the texts from the Russian National
Corpus since 1956, we compiled a list of 201 most common two-word combinations that have pairs
among one-word units. Seven two-word units, which are high-frequency or comparable in frequency
with their one-word counterparts, were considered the most likely candidates for entering the
mental lexicon of a Russian speaker. The next step will be the analysis of the phonetic realizations
of these units in natural Russian speech.