How many words do you need to know to be fluent?

Native speakers' vocabularies vary widely within a language, and are especially dependent on the level of the speaker's education. A 1995 study shows that junior-high students would be able to recognize the meanings of about 10,000–12,000 words, whereas for college students this number grows up to about 12,000–17,000 and for elderly adults up to about 17,000 or more.

The knowledge of the words deriving from the 3000 most frequent English word families and the 5000 most frequent words provides a comprehension of 95% of word use, and knowledge of 5000 word families is necessary for 99.9% word coverage.

There are many English learners who know 8,000 words, but they cannot speak a single sentence. On the other hand, there are people who know only 2,000 words and they can speak fluently. The difference is how deeply you know a word. Knowing 10,000 words passively will not help you with speaking. Instead focus on learning the first 2,000 words deeply.

Your goal should be to increase the depth of your vocabulary knowledge instead of the breadth of your vocabulary knowledge.

Learning vocabulary by memorizing the definition in your native language is an inefficient way to learn words. Rather, reading is the best way to increase your vocabulary. Learn words by seeing the word in a sentence. You can look up words in a dictionary, but study them in sentences, not the word itself.

There are roughly 100,000 word-families in the English language. A native English speaking person knows between 10,000 (uneducated) to 20,000 (educated) word families.

• 250 words constitute the essential core of a language, those without which you cannot construct any sentence.

• 750 words constitute those that are used every single day by every person who speaks the language.

• 2500 words constitute those that should enable you to express everything you could possibly want to say, albeit often by awkward circumlocutions.

• 5000 words constitute the active vocabulary of native speakers without higher education.

• 10,000 words constitute the active vocabulary of native speakers with higher education.

• 20,000 words constitute what you need to recognize passively in order to read, understand, and enjoy a work of literature such as a novel by a notable author.