How much vocabulary do you need for fluency?

You see, before we can count words, we need to define what exactly a word is. And that’s more difficult than you think. For example, let’s look at a simple word like dog. Dog has noun, and verb, and adjective forms. Are they separate words? What about the conjugations? What about hot dog? Or sheep dog?
Why is any of this important? Because a common question that learners have is “How many words do I need for fluency?” If you ask the internet you’ll get various different responses:
- “About 2-5k active words you know and use well.”
- “For daily conversations I already got quite far with around 500 words.”
- “Depends on the language. Some languages use less words than others, but each word carries a wider meaning.”
- “I’d say around 5000 words in most languages is going to get you into that ‘conversationally fluent’ level.”
- “Most people generally suggest around 2000 words to carry a simple conversation.”
Not very helpful. Maybe we could look to science for the answer? This 2016 paper estimates that the average 20-year-old native speaker of American English knows 42,000 words and 4,200 multiword expressions. Maybe that’s a good guide to the number of words you need for fluency?
No. And the reason is Scrabble.
Nigel Richards is the 2017 and 2018 French Scrabble champion. He is a phenomenon. The other French players described him as an ‘extra terrestrial’ and ‘a machine’ with ‘a perfect command of French vocabulary’.
But here’s the thing: Nigel Richards isn’t French. He’s from New Zealand. He doesn’t even speak French. He just memorised the French dictionary.

Certainly his recent success was not thanks to a secret fluency in French. “He’s not a francophone, I can confirm that,” Yves Brenez, the vice president of the Belgian Scrabble federation and organiser of the Francophone championships, told FranceTV. “Nigel will say ‘bonjour’ with an accent and he can also give the score in French, which is obligatory, but that’s all.”
So although he knows more French vocabulary than most French people, his fluency in French is ZERO.
So, how many words do you need for fluency?
The answer is that you’re asking the wrong question. It’s a bit like asking how many tomatoes you need to make the perfect Neapolitan pizza. You need tomatoes, good tomatoes, but you also need flour, yeast, water, salt, mozzarella, basil, and extra virgin olive oil. All of those ingredients come together to produce something beautiful.
So instead of asking how much vocabulary you need for fluency, you should ask ‘how much practice do I need for fluency?’.
And the answer is: A LOT.
Now, I’m not saying that vocabulary isn’t important. In fact, vocabulary size is a good indicator of language ability. But it’s not as important as you think, and it’s not enough on its own. You don’t NEED a lot of vocabulary. This study shows that using a lot of advanced vocabulary actually makes you appear LESS intelligent. And this study shows that the three most common ways to memorise vocabulary: flashcards, clozes, and crosswords, are not very effective.
Now maybe you think I am trying to sell you ‘the easy way’. ‘Learn a language without memorising vocabulary’. But it’s not that. Memorising vocabulary IS easy. Anyone can sit down with a list and memorise. What’s hard is taking a risk and entering into conversation. Sharing your thoughts, and ideas, and personality. If you want to be successful at learning a language you can’t hide behind language learning apps on your phone that only teach you how to memorise things.
Vocabulary is nothing without grammar, and pronunciation, and rhetoric, and the art of conversation, and something to say. We must always approach our language learning with a view to communication because language is not something to memorise, it’s something to use.