This paper advances a new country‐level measure of ethno‐linguistic diversity, making use of Greenberg's definition of diversity by synthesizing information on the share of different ethno‐linguistic groups in a country's population and, more importantly, information on intergroup linguistic distances derived from a recently developed lexicostatistical approach. I show that this measure captures ethno‐linguistic diversity at lower levels of linguistic aggregation. However, unlike the commonly used phylogenetic language tree approach, I found that these distance‐weighted diversity measures continue to have a strong negative statistical association with economic growth that is not sensitive to the underlying resemblance function between ethno‐linguistic groups.