It’s hard to say exactly how many words the English language has — some estimate there are up to 1 million. English always growing and evolving. When you consider slang, scientific words, and words borrowed from other languages, the number is huge and only getting bigger.
But how many words do you really need?
The answer depends on what you want to do with English. Basic conversation requires a smaller vocabulary than graduate school, for example. If you plan to go to an English-speaking university, you‘ll need to learn academic level vocabulary (the Academic Word List is a great place to start). If you’re studying English for your professional life, you should study business vocabulary. You may also need specialized vocabulary, like medical or information technology terms.
The good news is that a basic knowledge of English vocabulary can get you far. According to a research study, just 1000 words make up 72% of written English. That means that if you understand 1000 common words, you can understand almost ¾ of what you read. That’s a very basic level of vocabulary that most students can get quickly. Once you know 6000 words, you can understand 90% of what you read. And at 16,000 words, you will understand 98% of what you read.
Spoken English uses a smaller range of words. One researcher says that if you understand 2000 words, you can understand 96 percent of spoken English.