The article describes genre features of the written monuments in «Сlear Script». In the 17th century, along with the translated works in “Clear Script” there appeared original works of various genres, so that folklore texts were also literary edited. Because of the syncretism of many works of written literature (and written monuments) of the Mongolian peoples, it is rather difficult to define their genre precisely. Scientists, considering the genre characteristic of “early” texts, revealed its conditional character and concluded that the variety of the written heritage of the Oirats and the Kalmyks can’t be limited by any gradation of genres. Thus, all original works of the past centuries, primarily historical essays, formal written documentation, as well as folklore works will be selected as the text sources for the subcorpus of the “early” texts. These valuable works convey a vivid world of the Oirat and the Kalmyk people’s way of life in the XVII-XIX centuries. Handwritten historical essays, business letters, namtaru and other works of original genres are of special cultural value, as they reflect, albeit in a limited way, the state of the Oirat-Kalmyk language of its time and carry information about the grammatical system of the Kalmyk language. The language evolved and became what we call today “modern Kalmyk language”.