• The Index of Linguistic Diversity (ILD) is a measure of the diversity of languages spoken in a country or region.
• It is calculated by taking into account the number of languages spoken, the size of the language communities, and the level of mutual intelligibility between languages.
• The ILD ranges from 0 to 1, with 0 representing no linguistic diversity and 1 representing total diversity.
• A country with a high ILD has a large number of languages spoken by relatively small communities, while a country with a low ILD has a small number of languages spoken by relatively large communities.
• The ILD is a useful tool for understanding the linguistic diversity of a country or region. It can be used to identify areas where language diversity is threatened and to develop policies to protect endangered languages.
• The ILD was developed by Terralingua, a research organization that studies language diversity. The ILD is based on the work of Joseph Greenberg, who developed a measure of linguistic diversity called the Diversity Index.
• The ILD is a refinement of the Diversity Index that takes into account the size of the language communities and the level of mutual intelligibility between languages.
• The ILD has been used to measure the linguistic diversity of countries around the world. The results of these studies have shown that linguistic diversity is declining globally.
• The ILD for the world as a whole was 0.8 in 2005, which means that there has been a 20% loss of linguistic diversity since 1970.
• The decline in linguistic diversity is due to a number of factors, including globalization, urbanization, and the spread of dominant languages. Globalization has led to the spread of English and other major languages around the world.
• Urbanization has led to the decline of minority languages in urban areas. The spread of dominant languages can threaten the survival of minority languages, as people are more likely to adopt the dominant language for economic and social reasons.

Language extinction, also known as language loss or language endangerment, is a global phenomenon affecting many countries, including India. India is a linguistically diverse country with a rich tapestry of languages. However, this linguistic diversity also makes it susceptible to the challenges of language endangerment and extinction. Here are some key points regarding language extinction in India:

1. Linguistic Diversity: India is home to a staggering number of languages, with estimates ranging from over 1,500 to 2,000 distinct languages. This linguistic diversity is a reflection of India's complex history, cultural heritage, and the presence of numerous ethnic and tribal groups.

2. Language Families: Indian languages belong to several language families, including Indo-Aryan, Dravidian, Austroasiatic, Sino-Tibetan, and others. The Indo-Aryan and Dravidian language families are the most widely spoken and dominant language groups in India.

3. Endangered Languages: Despite the linguistic diversity, many languages in India are considered endangered. Factors such as globalization, urbanization, migration, and the dominance of major languages like Hindi and English have put smaller languages at risk.

4. UNESCO's Atlas of the World's Languages in Danger: UNESCO's atlas categorizes languages into different levels of endangerment. India has several languages listed as "critically endangered," "severely endangered," and "definitely endangered." For example, many tribal languages in India fall into these categories.

5. Government Initiatives: The Indian government recognizes the importance of preserving linguistic diversity. It has implemented policies and programs to protect and promote endangered languages. For instance, the "Scheme for Protection and Preservation of Endangered Languages" (SPPEL) supports research, documentation, and revitalization efforts for these languages.

6. Local Efforts: Many grassroots organizations, researchers, and community members are actively involved in efforts to document, revitalize, and promote endangered languages. These efforts often include language education, cultural preservation, and awareness campaigns.

7. Language Shift: One of the primary drivers of language extinction is language shift, where speakers of endangered languages switch to speaking more dominant or economically advantageous languages. This shift can result in intergenerational language loss.

8. Cultural Implications: Language extinction is not just about words and grammar; it also signifies the loss of cultural heritage, traditional knowledge, and identity for the affected communities.

9. Documentation: Linguists and scholars play a crucial role in documenting endangered languages. Linguistic documentation involves recording and analyzing the structure and vocabulary of endangered languages for future reference.

10. Language Revitalization: Efforts to revitalize endangered languages include language teaching programs, the development of teaching materials, and raising awareness about the value of linguistic diversity.