In most languages, it is the affixes that are realized as null morphemes, indicating that the derived form does not differ from the stem.
[citation needed] Null derivation, also known as conversion if the word class changes, is very common in analytic languages such as English.
In languages that show the above distinctions, it is quite common to employ null affixation to mark singular number, present tense and third persons.
Another unusual usage of the null morpheme is the feminine genitive case plural in most Slavic languages, cf.
[4] A basic radical element plus a null morpheme is not the same as an uninflected word, though usage may make those equal in practice.