In reduplications sometimes different words are used; sometimes words with similar or synonymous meanings, sometimes words with a lifelong meaning. Sometimes, one of the initial sessions of the reduplication is repeated, with changes. There are also cases where the uses used in reduplications are meaningful, while one is meaningful and the other is meaningless. Reduplications are structures that hold significant place in words and require long years of continuation to form, and they are the interruption of what is still unclear. This study examines the origin, structure, and classification of the commonly used reduplication “kap kacak” in Turkish. First, it discusses definitions of reduplications, their terminology in different languages, new terms suggested by researchers for reduplications, their classification, common misconceptions about reduplications, and previous studies on them. Then, it examines the usage of the words “ka,” “kap” and “kacak,” and their derivatives, in historical Turkic dialects. Examples of reduplication usage in modern Turkic dialects such as Kazakh, Gagauz, Altai and Karaim Turkic are provided. The study also examines whether the words “ka,” “kap” and “kacak” appear in etymological dictionaries and includes researchers’ opinions on these words. In the conclusion proposes an analysis of the origin and morphology of the words forming the “kap kacak” reduplication, the purpose of the suffixes used, and how the reduplication should be classified. Finally, it attempts to analyze the etymology of the words in the reduplication.

Kap kacak, ka, reduplication, DLT, historical Turkic dialects.