How many words are in a typical modern person's vocabulary?

well, I heard it is about 5000 words!

5000 may be the number of words a typical person uses. When it comes to vocabulary, it is important to distinguish between the words someone understands, and the words they actually use. An average adult with English as a first language understands between 50,000 and 250,000 words. Some people with very large vocabularies, such as Winston Churchill, have been estimated to understand up to 400,000 words. Most people actually use about 10% of the words they understand. So a person who understands 50,000 words probably uses about 5,000. Shakespeare used about 29,000 words in his plays & sonnets, so we might estimate that he had a vocabulary of 290,000 words. Note: There are at least 475,000 words in the English language, with some estimates as high as 1,000,000. And there are thousands added every year (Twitter, anyone?). So, there's lots to learn.