The Slavic languages mostly continue the Proto-Indo-European system of three genders, masculine, feminine and neuter. Gender correlates largely with noun endings (masculine nouns typically end in a consonant, feminines in "-a" and neuters in "-o" or "-e") but there are many exceptions, particularly in the case of nouns whose stems end in a soft consonant. However, some of the languages, including Russian, Czech, Slovak and Polish, also make certain additional grammatical distinctions between animate and inanimate nouns: Polish in the plural, and Russian in the accusative case, differentiate between human and non-human nouns.