What we do
Index of Linguistic Diversity 2020
We help people see the big picture

We create innovative measures of the world’s biological and cultural/linguistic diversity—and how they intersect as biocultural diversity. More than just numbers, our indices are tools that unlock people’s understanding of how different species, languages, and cultures enrich the planet.


A major upgrade for a leading index

First published in 2010, the Index of Linguistic Diversity (ILD) measures trends in the viability of the world’s languages by calculating changes in the fraction of the total population that speaks each one.  To use an economic analogy, it is an index of the average market share of languages. If the ILD trendline goes down, it means more and more people are speaking fewer and fewer languages.

The ILD has been adopted by the Convention on Biological Diversity as the benchmark measurement of progress toward its target of conserving traditional knowledge of indigenous and local communities.


One of our two primary projects at present is creating a second, expanded edition of the ILD. The ILD 2020 will include all 7,000+ languages, and will be calculated at the global, regional, and national levels. ILD 2020 is designed to be the most comprehensive quantitative assessment of the world’s linguistic diversity ever undertaken.

Who we are
Red List of Languages

Jonathan Loh and David Harmon are the co-investigators behind biocultural.info. Since 2002 we have collaborated on indices and other analyses of biocultural and linguistic diversity, publishing the results in books, scholarly papers, and op-eds.

Our other primary project is to expand and update our 2014 Red List comparison of the extinction risk of species and languages. By applying Red List analyses—the world standard for assessing the status of biological species—to languages, we think a more comprehensive picture of the twin extinction crises emerges.

We measure the world’s biocultural diversity so people will understand and value it.
Largest languaages