-ывать

Usage notes
The frequentative and imperfectivizing suffixes are etymologically the same. The suffixes are used with verbs in and  (in the latter case, the underlying root reappears, which may involve an extra consonant that was lost before the -н- of the verbal suffix). They are also used with some verbs in. The spelling variant is used instead with verbs that end in root-final velars (к г х) and hushing consonants (ш ж ч щ). The stress is drawn onto the syllable before the suffix, and an о in that syllable usually changes into а (examples:, , ; exception: ).