According to Ethnologue.com, there are nearly 7,000 languages spoken across the world today. Only a fraction of these languages (359) are truly global, spoken by millions of people. These include Mandarin Chinese, English, Spanish, and Hindi. The remaining 6,550 languages have a much more limited scope, and many are in danger of being lost entirely. To put the dichotomy in perspective, 94 percent of the world's population speaks 6 percent of its languages, while six percent of the world's population speaks 94 percent of its languages.

The Linguistic Diversity Index measures the diversity of languages spoken in a country. The scale ranges from 0 to 1. An index of 0 represents no linguistic diversity, meaning that everyone speaks the same language. An index of 1 represents total diversity, meaning that no two people speak the same language. No country has an index value of exactly 0 or 1.

The Linguistic Diversity Index can provide insight into the multicultural nature of countries. Some have high linguistic diversity because of their geographic position along trade routes. This is seen in the relatively high linguistic diversity in Kazakhstan, which was part of the Silk Road. Other countries have high linguistic diversity due to the presence of multiple, distinct ethnic groups, as seen in Bolivia, India, and Chad. Nations with low levels of linguistic diversity, such as Japan and Norway, are often culturally homogeneous.

The data source for this map is ethnologue.com, where the online version of the 16th edition of Ethnologue: Languages of the World is found.