This paper examines the relationship of productive variation in land between ethnic groups to determine if an increased range of producible goods will increase trade, thus decreasing language diversity between neighboring groups. The author initially found that high-variation in land production lessened the diversity of language between ethnic groups in that area. To further test this correlation, the author found that high-productive variation increased trade and exogamous marriage and decreased inter-ethnic conflict. Based on these findings, the author suggests that neighboring ethnic languages co-evolved through the economic benefit of inter-ethnic trade and social interaction.