 They propose that the distinctiveness of Kra-Dai (it is tonal and monosyllabic) was the result of linguistic restructuring due to contact with Hmong-Mien and Sinitic cultures.Aside from linguistic evidence, Roger Blench has also noted cultural similarities between the two groups, like facial tattooing, tooth removal or ablation, teeth blackening, snake (or dragon) cults, and the multiple-tongued jaw harps shared by the Indigenous Taiwanese and Kra-Dai-speakers.However archaeological evidence for this is still sparse.