The period of Eastern Islamic Turkish written language which lasts from 15th century to the 20th century, is generally known as Chagatay. Émiştük structure is seen in various works in pre-classical, classical and post-classical period. Gedayi, who was a pre-classical artist of Chagatay, preferred this structure in his works. This structure was also seen in the Divans of classical period artists such as Nevayi and Babür. In addition to these works of classical period artists, this structure was seen also in the post-classical period. This structure was seen in a dictionary called Ferheng-i Türki which was written in the postclassical period. Knowing that the analysis of this structure is difficult, in this article, whether this structure is evaluated in literature or not along with the evaluations are critically reviewed. The analysis of the structure of the émiştük is discussed by presenting proposals in this study. At the first glance, the structure “émiştük” looks like a conjoint declination. When we examine this structure deeply, we can evaluate that the structure does not allow the description of the conjoint declination with respect to personal endings. The relation between this structure and the morphem “-duk” in Divanü Lugati’t-Türk has been discussed and evaluated in this study. The structure of “émiştük”, which exists in Chagatay texts, can also be found in texts before and after Chagatay texts. The examination of various morphemes will be useful in order to understand on which bases Islamic Eastern Turkish written language has been developed.