The Old Uyghur language, which is often called the Uyghur-Oghuz language, means a large text corpus dating back to the 8t - 14th centuries. In these texts one can find a great number of words and phrases being difficult to interpret. To such difficulties nouns denoting religious terms and phenomena, and verbs are to be referred. The verb system in Old Uyghur gives us an opportunity to hypothesize about the efficiency of inflectional and lexeme formation processes that were used by the native speakers to transfer the information.