From 654.38+0.7 million to 654.38+0 million. There is no exact answer to this question, because English is constantly changing with the development of the times, old words are constantly being eliminated and new words are constantly being born. Some people say that Shakespeare's works have more than 10000 words. An average American college student knows about 30,000 words. Former Prime Minister Margaret Thatcher has a vocabulary of 30,000, which is rare in Britain. People in English-speaking countries usually only use about 3,000 to 5,000 words in their daily communication. As long as you master these basic common words, you can communicate normally. Those rare words, like those in Chinese, may not be used for a lifetime, so there is no need to learn them.