Phylogenetic inference for function-valued traits: Speech sound evolution

Phylogenetic models have recently been proposed for data that are best represented as a mathematical function (i.e. function valued). Such methods can be used to model the change over time in function-based descriptions of various data of interest to evolutionary biologists, including the sound of speech. This approach to phylogenetic inference and analysis is challenging, both in terms of modeling the phylogenetics of functions and in engaging with previously existing evidence for character-state change. Nevertheless, it is both a real and exciting prospect. Our approach could provide those interested in investigating a greater range of evolutionary processes with the ability to use statistical hypothesis-testing procedures and to create estimates of the states of function-valued characteristics (e.g. speech sounds) at earlier historical times. © 2011 Elsevier Ltd.