* Defining "Ethno-linguistic Group" is Complex: The terms "ethnic group" and "language" can overlap and be defined differently. Some might focus on shared cultural practices, others on language, and some on both.
* Constantly Evolving: Cultures and languages are dynamic. New groups can emerge, and existing ones can merge, split, or change over time.
* Lack of Consistent Data: There's no central authority tracking all ethno-linguistic groups worldwide. Data collection and categorization are often inconsistent.
However, estimates can be found:
* Ethnologue: This database, focused on languages, estimates over 7,100 languages spoken globally. While not directly corresponding to ethno-linguistic groups, it provides a starting point.
* UNESCO: Their "Atlas of the World's Languages in Danger" highlights the diversity of languages but doesn't offer a global count.
Therefore, a precise number for ethno-linguistic groups is elusive. It's more accurate to say there are thousands, with estimations ranging from thousands to tens of thousands, depending on the criteria used.