Aspects of language vary in their rates of evolution and subsequently different languages may accumulate different amounts of lexical change once they split from a common ancestor. Linguists propose a number of driving factors for differences in rates of change. Here, following simple theoretical models borrowed from population genetics, I test for an association between lexical change and a demographic variable, language population size, in the Austronesian languages. Conventional correlation analyses reveal a significant inverse relationship, suggesting that as population size increases, lexical change decreases. However, phylogenetic comparative methods that control for shared descent produce different results, demonstrating once again that history matters.