When a text represents both language and culture codes, linguacultural lexicography and phraseological phenomena need to be examined. The current study utilized a qualitative research design with a linguacultural and historical approach to examine Ahmed Yasawi's "Diwani Hikmet," a collection of Sufi poetry of the medieval period. A theoretical framework of decoding stylistics guided this research study, supported by Arnold's (1972) theory of Decoding Stylistics. The study focused on the principles of convergence, the inconceivable effect and coupling to understand the language and cultural codes in Yasawi's mystic poetry. Due to its alignment with the perspective of Kazakh linguistics, "Diwani Hikmet" was analyzed through a methodological perspective covering the philosophical, historical, cognitive, and cultural aspects of Yasawi's legacy The Samarkand version of "Hikmet" and Zharmukhameduly's word for word translation were used to take examples of Yasawi's poetry for determining the language and cultural codes. This study revealed what decoding procedures should be used to understand Yasawi's "Diwani Hikmet" and to identify linguistic and cultural codes. During the process, stylistics decoding process was adopted and tools such as convergence, inconceivable effect, and coupling enabled the understanding of the language and cultural codes in his poetry. The findings revealed that linguistic units in "Diwani Hikmet" are not only language specimens but they also contain cultural significance, as they presented the moral and didactic elements as well. The text thus supported both the artistic and aesthetic functions. This study would have both literary and cultural implications since this study represents the wisdom of the Turkic people.