* No Comprehensive Record: We don't have a complete record of every language that has ever been spoken. Many languages were only spoken orally and never written down.
* Language Change and Evolution: Languages constantly evolve and change over time. It's difficult to determine when a language has become distinct enough to be considered a separate language from its parent language.
* Regional Dialects: Even within a single language, regional variations can be significant. Are those dialects separate languages or just variations?
Estimates:
While there's no precise number, estimates range widely.
* Ethnologue: A widely used reference book on languages, Ethnologue estimates that there are around 7,100 living languages today. This number is likely to be a significant underestimate of the total number of languages that have ever existed.
* Other Estimates: Some experts believe that thousands, perhaps tens of thousands, of languages may have been spoken throughout history.
The Bottom Line:
We can confidently say that thousands of languages have existed throughout history, but the exact number is unknown and likely unknowable.