* Definition of a word: What constitutes a "word" is subjective. Do we count proper nouns, technical terms, slang, and regionalisms? What about variations like plural forms or verb tenses?
* Constantly evolving language: Languages are dynamic. New words are constantly being coined, and old words fall out of use. Dictionaries struggle to keep up.
* Language diversity: There are thousands of languages spoken around the world, each with its own unique vocabulary.
However, we can offer some estimates:
* English: The Oxford English Dictionary contains over 600,000 entries, but this only represents a fraction of the words that have ever existed or are currently used.
* Global estimate: Some linguists estimate that there are millions, perhaps even tens of millions of words across all languages.
Ultimately, the number of words is a constantly shifting target, and any attempt to quantify it is likely to be a gross underestimate.