* No universally agreed definition of a dialect: There's no clear line between a dialect and a separate language. Some criteria include mutual intelligibility, shared history, and social factors.
* Continuum of variation: Languages often gradually shift from one area to another, with dialects merging and diverging. This makes it hard to draw distinct boundaries.
* Lack of comprehensive documentation: Many languages and dialects, especially in remote or under-documented areas, haven't been thoroughly studied or classified.
Estimates and Considerations:
* Thousands: Most linguists agree that there are thousands of dialects worldwide. Some estimates range from thousands to tens of thousands.
* Focus on languages: It's more common to talk about the number of languages in the world (around 7,000), with the understanding that each language has multiple dialects.
* Regional variation: The number of dialects can vary dramatically between regions. Some areas have high levels of linguistic diversity, while others have fewer dialects.
Key takeaway: While we can't put a precise number on the world's dialects, it's clear that there is a vast amount of linguistic variation across the globe.