Foreign text intelligibility: case of Slavic language group

The research concentrates on the intelligibility of languages for a speaker of a related language. Our hypothesis is that people can partially understand text in a language related to their native language, and the closer the relation, the more they can understand. In order to check that we conducted a series of experiments where we asked native speakers of Russian to fill the gaps in a Russian text using its translation into another Slavic language (Ukrainian, Belorussian, Bulgarian, Polish, or Czech). As a baseline we took the Estonian language, which is very different from Russian in many aspects and cannot be understood by a Russian speaker without training.
The results show that a native speaker of Russian performs the gap filling task significantly better when provided with the translation of the text into a Slavic language.