Tianshin Jackson Sun (Sun 1992, Sun 1993) was the first to suggest the phylogenetic relatedness of a number of highly divergent, endangered and poorly described languages of Western Arunachal Pradesh, later named the ‘Kho-Bwa cluster’ by Van Driem (2001). In this paper, we make use of what are predominantly new data from our own field work, covering a total of 22 linguistic varieties. In a list of 100 lexical entries, cognate roots were tagged and subsequently a pairwise “cognacy percentage” was computed which forms the basis for a hierarchic cluster analysis. The result of this analysis and some further considerations confirm earlier reported views of a phylogenetic relationship between these languages. The appendix contains the full data set with cognacy statements. All computer code is available and documented on Github (https://github.com/metroxylon/kho-bwa-lexicostat).