* Dictionaries vary: Different dictionaries have different criteria for what counts as a word (e.g., proper nouns, technical terms, slang).
* Words evolve: New words are constantly being created, and old words fall out of use.
* Regional differences: English has many dialects and regional variations, each with its own unique vocabulary.
Estimates:
* Oxford English Dictionary: Claims to have over 600,000 entries, but this includes historical and technical words, not all of which are in common use.
* Merriam-Webster: Estimates around 470,000 words in common use.
So, the bottom line is: While there are estimates, it's impossible to give a precise number for the total number of words in English. The number is constantly changing and depends on how you define "word" and what sources you consider.