Language is shaped by the cognitive biases of its speakers (Christian & Chater, 2008) and evolves in punctuational bursts of change following events associated with speciation (Atkinson et al., 2008). But what causes a new language to emerge in the first place? One theory is that important moments in cultural evolution facilitate the emergence of new languages. For example, the Farming/Language dispersal hypothesis contends that languages spread along with the expansion of agriculturalists across the globe whether by cultural diffusion or by Landnahme events (Diamond & Bellwood, 2003). With the application of phylogenetic methods to model the history of the evolution of languages, such speciation events are given elegant timescales that may be used to explore what causes the emergence/divergence of languages. This thesis presents a historical-comparative study of Japanese to languages of mainland East Asia to test the results of Lee and Hasegawa’s (2011) phylogenetic analysis of Japanese which suggests that the emergence of Japanese coincides with the spread of agriculture to the isles from Korea. By comparing agricultural terminology based on empirical evidence from archaeology and genetics, this thesis provides the first comprehensive examination of this theory.