Taking Miyagawa’s (2022. Syntax in the treetops. Cambridge, MA: MIT Press) discussion as a point of departure, I examine the properties of the formal politeness markers in Japanese and Korean, namely, -mas/-des and -(su)pni. Besides being markers of formal politeness (or allocutive agreement), these elements are parallel in that they are all limited to Emonds’ (1970. Root and structure-preserving transformations. Ph.D. dissertation, MIT) root contexts and are able to license special interrogative particles, which according to Miyagawa (2022. Syntax in the treetops. Cambridge, MA: MIT Press) is a consequence of their head-to-head φ-feature movement. In addition to the systematic similarities, there is an important difference concerning their base-generation in TP-internal and TP-external positions, which I suggest reflects a general pattern of grammaticalization in these languages. In addition to providing support for Miyagawa’s analysis, the discussion in this paper also shows that aspects of the behavior of Japanese and Korean, such as the formal politeness markers -mas/-des and -(su)pni, can generally be better understood when they are analyzed side-by-side rather than in isolation.