How many words do you need to read a language?
Drag the slider to choose how many English words you know. Every word you wouldn't know turns into a made-up one, and the redder it is, the further you are from knowing it.
Why 90 percent isn't enough
Ninety percent sounds like nearly everything. But it's one unknown word in ten, and they're the words that carry the meaning. Hu and Nation (2000) tested it this way: they swapped words in a short story for nonsense words and asked readers what happened. At 80 percent, nobody followed it. Most readers needed about 98. Pick 90 below and try to say what Alice is doing.
Each thousand words buys less
The most common words are everywhere, so your first thousand covers most of a page. After that, each thousand covers less than the one before. Keep pressing the button and watch the bars shrink.
That's why the last few percent take so long. Reading novels and newspapers at 98 percent takes around 8,000 to 9,000 word families (Nation, 2006), and conversation about 6,000 to 7,000. At 95 percent, roughly 4,000 to 5,000, you can follow the gist (Laufer & Ravenhorst-Kalovski, 2010).
Some texts need far more words than others
A story uses everyday words. A recipe is full of kitchen words like simmer and cumin that you rarely see anywhere else. Drag across the chart to compare them.
It cuts both ways. Read a lot about one subject and its words keep coming back, so they stop being rare for you.
What it means for learning Spanish
- Learn the most common words first. They're the cheapest progress you'll ever make.
- Read things where you know nearly every word. That's where the few new ones are easy to guess, and guessing from context is how most words get learned. More in comprehensible input.
- Use what you already know. Thousands of Spanish words look like English ones, like temperatura and posible. Spanish cognates shows the patterns.
How it works
The word list ranks about 25,000 English word families by how often they're used, from wordfreq (Speer, 2022). A family is a word with its forms, so walk, walked and walking count once, as they do in the research. Names count as known. It's a model: nobody learns words in exact frequency order, and the thresholds are averages, not cliffs (Schmitt, Jiang & Grabe, 2011).
Questions
How many words do you need to know to understand a text?
About 98 percent of the words in it to read comfortably on your own (Hu & Nation, 2000). At 95 percent most people can follow the main points. Below 90 percent it usually falls apart.
How many Spanish words do I need to be conversational?
Fewer than for reading, because speech uses a smaller set of words. For English, Nation (2006) puts 98 percent of everyday speech at 6,000 to 7,000 word families, and Spanish follows the same shape. You can hold a simple conversation long before that.
Can I use this with my own text?
Yes. Choose "Your own" and paste any English text. It runs in your browser, and nothing you paste is sent anywhere.
Sources
- Unknown vocabulary density and reading comprehension. Hu & Nation, Reading in a Foreign Language 13(1), 2000.
- How large a vocabulary is needed for reading and listening?. Nation, Canadian Modern Language Review 63(1), 2006.
- Lexical threshold revisited: Lexical text coverage, learners' vocabulary size and reading comprehension. Laufer & Ravenhorst-Kalovski, Reading in a Foreign Language 22(1), 2010.
- The percentage of words known in a text and reading comprehension. Schmitt, Jiang & Grabe, The Modern Language Journal 95(1), 2011.
- wordfreq: word frequencies in many languages. Robyn Speer, 2022.
Keep going
- What comprehensible input isComprehensible input explained: what it is, where the idea comes from, what the research says about vocabulary thresholds, and why reading and listening at the right level beats drills. With sources.
- Spanish cognatesSpanish cognates explained: -tion → -ción, -ity → -idad, -ous → -oso, -ist → -ista and -al → -al, with pronunciation, gender and false friends to watch for.
- How long does it really take to learn Spanish?Realistic numbers for how long it takes an English speaker to learn Spanish, level by level, from the Foreign Service Institute and CEFR estimates, and what actually makes the hours count.