In this paper, on the basis of theoretical approaches, the evaluation of a descriptive study on the phonology of Turkish and how to use such a study in language teaching are discussed. The mentioned descriptive study is a model study in the framework of linguistic analysis and language teaching. This paper comprises three main parts. In the first part, the theoretical linguistic and phonetic studies are examined. In the second part, a descriptive study on Turkish phonetics by Jaklin Kornfilt is evaluated as a model study regarding its association with the linguistic theories. In the third part, the benefits of systematic and descriptive studies on practical studies and the issue of theory and practice relationship are discussed.