Hittite and Tocharian share an interrogative pronominal stem in m-next to the well known Proto-Indo-European interrogative *kʷi-, *kʷe-, *kʷo-. In Tocharian, the m-interrogative is especially... Show moreHittite and Tocharian share an interrogative pronominal stem in m-next to the well known Proto-Indo-European interrogative *kʷi-, *kʷe-, *kʷo-. In Tocharian, the m-interrogative is especially frequent as a formative element in several interrogative, relative and indefinite stems. In this paper, these stems are investigated in detail, and it is argued that the Tocharian A interrogative stem ā-posited by Sieg, Siegling & Schulze in their Tocharische Grammatikis a ghost. Although the reconstruction of the m-interrogative for the oldest stage of Proto-Indo-European is beyond any doubt, it is difficult to use this Anatolian-Tocharian isogloss as an argument for the phylogenetic structure of the Indo-European family tree since in the other branches the m-interrogative may have been lost independently. Show less