Multi-Agent Simulations of the Evolution of Combinatorial Phonology

A fundamental characteristic of human speech is that it uses a limited set of basic building blocks (phonemes, syllables), that are put to use in many different combinations to mark differences in meaning. This paper investigates the evolution of such “combinatorial phonology” with a simulated population of agents. We first argue that it is a challenge to explain the transition from holistic to combinatorial phonology, as the first agent that has a mutation for using combinatorial speech does not benefit from this in a population of agents that use a holistic signaling system. We then present a solution for this evolutionary deadlock. We present experiments that show that when a repertoire of holistic signals is optimized for distinctiveness in a population of agents, it converges towards a situation in which the signals can be analyzed as combinatorial, even though the agents do not use this structure. We argue that in this situation adaptations for productive combinatorial phonology can spread.