Since the era of the Uighur khanate (ethnopolitical association), who came in the history after the Old Turkic Empire, instead of Old Turks writing a new inscription was used under the religious influence of the Manichaeism of the Sogdian people. In the 9-14th centuries Old Turks developed the Old Uighur writing, adapted to the nature of the Turkic language and based on the Sogdian writing, the letters were written from the top to the bottom in the vertical direction and changed the form of the beginning, middle part, and the end of the word, and were written one after the other in a row. This alphabet included about 20 letters, where vowel sounds such as а-е, і-ы, о, ұ, ө, ү were written with 4 letters, and only one letter for each group of consonant sounds ғ-қ-х, г-к, б-п.