* No Universal Dictionary: There's no single dictionary that encompasses all languages.
* New Words Constantly Emerge: Languages are dynamic and evolve. New words are constantly being created, borrowed, and adapted.
* Defining "Word" is Complex: What constitutes a word can be debated. Do we include slang, technical terms, proper nouns, or words in specialized contexts?
However, we can estimate:
* The number of languages: There are estimated to be between 6,000 and 7,000 languages spoken worldwide.
* Average number of words per language: This varies greatly. Some languages have tens of thousands of words, while others have hundreds of thousands.
Therefore, the total number of words in all languages is likely in the millions, if not billions. But it's an impossible number to pin down with accuracy.