* Defining "language" and "dialect" is complex. There's no universally agreed-upon definition.
* Mutual intelligibility is a blurry line. Two languages can be very similar, but not mutually intelligible, while two dialects of the same language might be largely understood by speakers of each.
* Constant evolution and extinction. Languages and dialects change over time, some merge, and some die out.
Estimates:
* Ethnologue - This widely used resource estimates around 7,100 languages, though it's important to note that these numbers include some dialects that some might consider separate languages.
* UNESCO - Uses a wider definition and estimates over 2,500 "living" languages based on UNESCO's criteria of "living languages" meaning they are used in daily life.
Important takeaway: We can't give a definitive number, but it's safe to say there are thousands of languages and dialects spoken around the world, each representing a unique cultural heritage and way of thinking.