Increased funding to preserve linguistic diversity

In a letter to Nature Yoshina Gautam and Aashish Jha ask for "increased funding [...] to preserve language diversity, particularly in developing countries." They don't say why but refer to the United Nations Permanent Forum on Indigenous Issues. According to the UNPFII the protection of indigenous languages is important because

• As a result of linguistic erosion, much of the encyclopedia of traditional indigenous knowledge that is usually passed down orally from generation to generation is in danger of being lost forever. This loss is irreplaceable and irreparable.

• Customary laws of indigenous communities are often set out in their languages, and if the language is lost the community may not fully understand its laws and system of governance that foster its future survival.

• The loss of indigenous languages signifies not only the loss of traditional knowledge but also the loss of cultural diversity, undermining the identity and spirituality of the community and the individual. 

• Biological, linguistic and cultural diversity are inseparable and mutually reinforcing, so when an indigenous language is lost, so too is traditional knowledge on how to maintain the world’s biological diversity and address climate change and other environmental challenges.

We stop to speak a language when we die or when we switch to another language. In the latter case we can still pass down our knowledge and laws by translating them or by importing some words to our new language. (Curiously, the UNPFII does not advocate this but the opposite - "translating laws and key political texts into indigenous languages so that indigenous peoples may better participate in the political and legal fields.")

But let's say that in some cases it is linguistically impossible to translate something or import the relevant keywords. I trust that most people who voluntarily stop speaking a language do so for their own good and the good of their children, so any possible losses of traditional "indigenous" knowledge, laws, identity, spirituality, biodiversity and solutions to climate change must be relatively unimportant to them. The same goes for people who decide not to learn an "indigenous" language - the advantages of doing so are probably not worth the effort for them.

But it is possible that speaking a certain language is not worthy for an individual but good for the rest of society. For example, if speaking a given language is a key to alleviating the problem of climate change much of the benefit may go to society as a whole and not to the speakers. In this case, it makes sense to pay some people to speak that language.

The UNPFII agrees and advocates "allocating the funding and resources needed to preserve and develop indigenous languages, and particularly for education [in the mother-tongue of indigenous children]." If we subsidize education in one language but not in other, then more people will get educated in the former, the risk of losing the language is smaller, and we are more likely to keep the key to the problem of climate change.

How much must we spend in those subsidies? If other things are equal and the administrative costs are small, the subsidies should be about as large as the benefits we all derive from climatic and environmental improvements brought about by knowledge that can't be translated. I don't know if that is a dollar or a billion dollars. Yoshina Gautam, Aashish Jha and the UNPFII don't say either.