Fig. 5.

The Z score measure of association between gene and language phylogenies on Sumba and Timor for different language switching rates $\alpha$. Language switching rates below ∼0.5% per generation are required to generate the type of association between languages and clades observed in the empirical data (Table 1). All cases independently converge and abruptly lose gene–language associations, behaving similarly to randomized cases, when the language switch rate exceeds ∼0.5% per generation. Inset zooms in to show the fine scale of inferred host-switching rates.