-ко • (-ko)
- Creates diminutives of neuter nouns and adverbs, normally having a colloquial register.
- The suffix is added to the stem of the word (i.e. minus its final vowel, if any). An epenthetic vowel often breaks up stem-final consonant clusters, and velars become palatals according to the Slavic first palatalization (both effects are due to the yer that occurred at the Proto-Slavic level). These effects can be seen in тихо́нечко (tixónečko, “very quiet”), derived from тихо́нько (tixónʹko, “quiet”), itself containing the same diminutive ending. (Specifically, starting from the stem *тихо́ньк-, a vowel is epenthesized, producing тихо́нек-, and the final velar is palatalized, producing тихо́неч-.) In general, the combination -ко + -ко produces -ечко (-ečko) or -очко (-očko).