This paper is concerned with the documentation, typology and diachrony of a single inflectional paradigm expressing inalienable attributive possession in Roon, a language of the South Halmahera West New Guinea subgroup of Austronesian. The paradigm in question exhibits a substantial amount of variation both within and across speakers. Formally, the paradigm is exceptional in that, in some of its variants, it makes use of an H toneme, the only attested usage of tonality in the entire language. Functionally, the paradigm is remarkable in that, in some of its variants, the possessor is distinguished not for person but rather for distal deixis. Historically, the H toneme forming part of the paradigm is argued to derive from the grammaticalization of a High Extended Intonation contour expressing excessivity along a scalar dimension, characteristic of many languages of New Guinea and Australia. In some languages of North West New Guinea, this intonation contour anchors to certain particles, resulting in ideophones such as the Papuan Malay eeeH . One such ideophone, it is suggested, was subsequently incorporated into the expression of inalienable attributive possession in Roon. The proposed analysis thus provides a case study of how intonation may develop into tone, and, more generally, how gesture may be incorporated into grammar.