Does a punctuation mark facilitate sentence readability? The tasks using sentences with syntactic ambiguity are suitable for such experimental studies. For example, the subjects deal with a specific pragmatic problem of relative clause (RC) attachment with complex noun phrase (NP) choosing early (N1 modification) or late (N2 modification) closure of ambiguous construction in Russian. Our experiment showed that the presence and absence of comma on RC boundary had different effects on individual interpretation strategies of a certain sentence as well as speech tempo in reading. The experiment showed that the role of punctuation factor in reading sentence in Russian with late closure prime was negligible. Null prime facilitated early closure preference, generally, but there were no significant differences in tempo pronouncing of the sentence segments. In addition, there was no correspondence between a pause and a comma on RC boundary. Comma absence in the sentence with early closure prime caused tempo slowing in pronouncing N1 and reducing preferences of early closure from 100% to 80%. The experiment revealed gender differences in tempo pronouncing of N1 depending on punctuation factor: the females tend to read N1 slower than males. This effect becomes stronger when the comma precedes RC.