Figure 6.

Frequency plots of the age of the Dravidian language family (tree height) for all models, with age in years from the present. Analyses are ordered by marginal log-likelihood, table 3, and electronic supplementary material, table S2. Models of cognate gain and loss included are (i) CTMC; (ii) CTMC plus γ rate heterogeneity with four rate categories (CTMC + γ); (iii) binary covarion (covarion); (iv) stochastic Dollo (Dollo). Models of tree rate variation are (i) strict clock; (ii) relaxed clock with rates sampled from lognormal distribution. Models of concept rate variation are (i) relative mutation rate estimated for individual concepts (word rates); (ii) no relative mutation rate estimated (overall rate).