Age of acquisition predicts rate of lexical evolution

• A direct link is established between language acquisition and language evolution.
• Early-acquired words change less rapidly as a consequence of language evolution.
• Language acquisition contributes to stability and not change in language evolution.
• Ultra-conserved words are consistent with sound-symbolism in origins of communication.

The processes taking place during language acquisition are proposed to influence language evolution. However, evidence demonstrating the link between language learning and language evolution is, at best, indirect, constituting studies of laboratory-based artificial language learning studies or computational simulations of diachronic change. In the current study, a direct link between acquisition and evolution is established, showing that for two hundred fundamental vocabulary items, the age at which words are acquired is a predictor of the rate at which they have changed in studies of language evolution. Early-acquired words are more salient and easier to process than late-acquired words, and these early-acquired words are also more stably represented within the community’s language. Analysing the properties of these early-acquired words potentially provides insight into the origins of communication, highlighting features of words that have been ultra-conserved in language.