photo by David Rapport, 2011

“Language allows us to interact with the world in so many ways, almost like seeds adapted to local conditions, land races that make the best use of local conditions.”
Felipe Montoya Greenheck 

The Index of Linguistic Diversity is the first-ever quantitative measure of trends in the world’s linguistic diversity. It tells us that, since 1970, global linguistic diversity has diminished by 20%. Indigenous linguistic diversity has decreased even more markedly in most regions of the world. The 16 largest world languages have increased their share of the world’s population from 45% to 55%. These trends should concern us all. Why?

What’s Happening with the World’s Languages?
The Index of Linguistic Diversity Tells the Story

Linguistic diversity is part and parcel of the diversity of life in nature and culture. Any loss in linguistic diversity is a loss in the vitality and resilience of the whole web of life. Every time a language disappears, along with the cultural traditions and cultural knowledge it conveys, it’s a piece of the planet’s living fabric that gets torn off, leaving all of the living world more fragile, more vulnerable, and with fewer options for the future.

There are about 7,000 languages spoken in the world today. However, the numbers of speakers of these languages are vastly uneven. To put it simply, there are a few languages each with a lot of speakers, and a lot of other languages each with a small number of speakers. In fact, the distribution is so skewed, that half of the world’s population speaks one or other of only 25 “big” languages, while the other half of the world’s population speaks one or other of the remaining 6,975 or so languages. And these smaller languages are increasingly losing ground to the “big” languages.

Distribution of Speakers Among Languages

Concern about the loss of diversity and vitality of the world’s languages has been building since at least the early 1990s.  Yet, this concern was mostly based on anecdotal evidence which suggested that many languages might become extinct by the end of the 21st century.  In 2005-2010, Terralingua collaborators David Harmon and Jonathan Loh took on the challenge of providing sold scientific evidence on the state and trends of the world’s languages.  They gathered systematic quantitative data and developed the first-ever Index of Linguistic Diversity (ILD).  The results of the ILD research were published in 2010 in a peer-reviewed article:

Harmon, D. and Loh, J. 2010. The Index of Linguistic Diversity: A New Quantitative Measure of Trends in the Status of the World’s Languages. Language Documentation & Conservation 4: 97-151.

The ILD reveals an alarming rate of decline in global linguistic diversity, showing that the world’s languages – not just their number, but also the linguistic and cultural diversity they represent – are being severely diminished.  In just 35 years, between 1970 and 2005, global linguistic diversity has declined by 20%.

Declining Trend of Global Linguistic Diversity, 1970-2005

ILD Regional Indigenous

Comparison of Regional Trends of Indigenous Linguistic Diversity, 1970-2005

The dramatic decline in linguistic diversity is due to ever-growing social and economic pressures that are inducing or even forcing people to switch from generally smaller, more geographically restricted languages to larger languages, especially global languages like Mandarin Chinese, Hindi, English, or Spanish, or regionally dominant languages like Swahili. The top 16 languages spoken worldwide increased their share of the global population from 45% in 1970 to 55% in 2005.

ILD Largest World Lanugages

Largest World Languages Increasing Their Share of World’s Population

The changes in the number of mother-tongue speakers are associated with shifts in the use of a given language in adult speakers, as well as with a decline in the transmission of that language to new generations.

The ILD data provide strong support to the claim that there is a global crisis of linguistic diversity loss. The ILD captures the magnitude of the problem in a way that is easy to understand and informative for researchers, educators, policy makers, and the general public.

The ILD was developed not only in order to document these trends, but also to influence world’s languages.  As well, the aim was to call attention to the importance of maintaining linguistic diversity for the conservation of biological diversity.  Earlier work that Harmon and Loh carried out for Terralingua (2001-2005) had led to the development of an initial Index of Biocultural Diversity (IBCD), which suggested parallels and connections between the state of the world’s linguistic diversity and the state of the world’s biological diversity.

The ILD has been chosen as one of the indicators relevant to Target 18 of the Convention of Biological Diversity “Aichi Biodiversity Targets 2010-2020″, an international initiative aiming to counter the global loss of biodiversity.  Aichi Target 18 recognizes the relevance of traditional knowledge (and of the languages in which traditional knowledge is encoded) for the conservation and sustainable use of biodiversity.  The ILD is featured on the site of the Biodiversity Indicators Partnership (BIP), which promotes and coordinates the development and delivery of biodiversity indicators in support of the CBC, and on the BIP’s “Aichi Passport“, a smartphone app that highlights the indicators.

Presentations of the ILD have taken place in numerous international fora, including the 4th World Conservation Congress (Barcelona, Spain, 2008), the 12th International Congress of Ethnobiology (Tofino, Canada, 2010), and the International Conference on Biological and Cultural Diversity (Montreal, Canada, 2010).

Harmon and Loh are now continuing their research independently, with a special focus on further documenting and analyzing the crucial links between linguistic and biological diversity.  For additional information on the ILD and the IBCD, you can download relevant materials on the Download page or email

David Harmon dharmon[at]georgewright.org

Jonathan Loh  jonathan[at]livingplanet.org.uk

We are deeply grateful to The Christensen Fund for its support of the IBCD and ILD in 2001 – 2010.


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