There are simple, compound and derivative verbs in the Sumerian language. Compound verbs are 'frozen' combinations of a simple verb and a permanent object. Derivative verbs are combinations of nouns, nomen actionis, interjections and verbs ag «to do» and dug4 «to say». In the course of time these verbs have become a kind of word-formative affixes. Idiomatic meaning of such combinations is attested by Sumerian-akkadian dictionaries and by Sumerian texts themselves. However, the components of these combinations have separate morphological markers and preserve their lexical independence: they function as parts of a sentence and can be incorporated in the prefix chain of finite verbal forms.