ABSTRACT
Diversity is the outcome of differences in the birth-rate and the death-rate of languages. Therefore, according to glottochronology, the tempo of language change is largely constant and varies little over time. The effect of population size on language diversity is perhaps nowhere more evident than in the New World. The advent of agriculture has been suggested as the major driver of language diversity. Geography affects language diversity by acting as a barrier to human contact. In fact, there was a highly significant correlation between latitude and diversity. There are therefore many hypotheses about how geography and ecology interact with language diversity. Language diversity shows a marked increase towards the equator. Social factors play a major role in affecting language diversity in many different ways. The ways that people organise themselves into societies also influences language diversity. Truly understanding language diversity will require us to understand how all the proposed drivers of diversity interact.
