How many words does an average native English speaker know?

The number of words an average native English speaker knows can vary depending on the source and the definition of "knowing" a word, but here are some consistent estimates:

Active and Passive Vocabulary

• Estimates suggest that the average native English speaker has a receptive (passive) vocabulary of around 20,000 to 30,000 words. This includes words they recognize and understand but may not actively use234.

Base Words and Word Families

• When considering "base words" or "word families" (which include a base word and its inflected forms and derivations), the average native speaker's vocabulary is estimated to be around 20,000 base words. Using a factor of 1.6 to account for total words, this translates to approximately 30,000 to 35,000 words2.

Detailed Studies

• A comprehensive analysis by researchers at Ghent University estimated that an average 20-year-old native speaker of American English knows about 42,000 lemmas (unique words or word roots) and 4,200 non-transparent multiword expressions, derived from 11,100 word families. However, this range can vary from 27,000 lemmas for the lowest 5% to 52,000 for the highest 5%4.

Everyday Usage

• It's important to note that in everyday communication, native speakers typically use a much smaller subset of these words. For example, about 95% of everyday talk is drawn from a pool of just 3,000 high-frequency words3.

In summary, while the exact number can vary, a reasonable estimate for the average native English speaker's vocabulary is between 20,000 to 35,000 words, with the understanding that only a fraction of these words are actively used in daily life.