Does Your Vocabulary Size Matter?

Whether you know tens of thousands of words, or are just getting started with the basics, word frequency can tell us a lot about our vocabulary.
Woman writing in a notebook writing vocabulary

Have you ever wondered how many words your vocabulary consists of, in English or any other language you speak? How many words do you actually use, and how many do you need if you’re learning a new language? And what type of vocabulary should you focus on? We’ll dig deeper into this topic.

How Many Words Do You Know?

To be able to discuss sheer numbers, i.e. how many words are in a person’s vocabulary, we need to know: what is a word? That’s easy, you might think. “You,” “might” and “think” are three different words. But is “think” and “thought” the same word? In Spanish, are soy and eres two different words? And if “dog food” is two words, does that mean that the German Hundefutter should also count as two? 

Most linguists agree that in dealing with text data such as vocabulary lists, it makes the most sense to count the lemmas. A lemma is a word in its most basic form, without its inflexions. Otherwise, it would be virtually impossible to compare languages to each other. Say, for example, that you would study Swedish and German at the same time and learn five words for “have” in German and only one in Swedish. It doesn’t necessarily make your German vocabulary larger by four words — it shows that you’re able to apply grammatical rules.

In taking inventory of your vocabulary, it might also make sense to only count dictionary entries, to avoid too many composite words whose meaning you can derive from knowing the words it’s made of, like Hundefutter. If you don’t, depending on the language you’re dealing with, you could very well end up with over 20 million unique words, as in the ever-growing German Duden-corpus. The English Merriam-Webster dictionary has around 470,000 entries. Many of the big world languages have about 100,000 to 500,000 words in their dictionaries, but these numbers don’t say much about actual usage: many words are archaic and barely in use anymore, or very specific for certain fields.

We get a better idea of which words are used in a language by looking at corpora – huge collections of texts from different sources, ideally diverse enough to mirror real language use. With such collections, you can start looking at the frequency and divide words in a language into different tiers. The most frequent words will be function words: determiners, prepositions, pronouns and common verbs like “be” or “have.” According to the text data used in Test Your Vocab, which is based on levels of frequency in a corpus, some of the least frequent words are such forgotten treasures as funambulist, braggadocio or myrmidon.

How Many Words Do You Need?

Adults who are native English speakers tend to have a vocabulary of 15,000 to 30,000 words, depending on who you ask and what you mean by vocabulary. The team behind Test Your Vocab has collected data from nearly 10 million (!) participants testing their vocabulary on their site and has found the most common range for adult test-takers to be between 20,000 and 35,000 words. In addition, the average 8-year old knows 10,000 words, and the median vocab size for a 40-year old is 30,000 words, with some people in their middle age ranging up to 38,000. Vocabulary seems to stops growing after 50 years of age. According to the same data, 4,500 words is the most common vocabulary size for non-native English test-takers. However, if they live abroad, they can score well over 10,000. When living in an English-speaking country, non-natives acquire 2.5 new words per day!

The test is based on whether you recognize and are able to define a specific word or not. It doesn’t tell us whether the test-takers use 20,000 unique words actively over a month or even a year. That’s a lot more difficult to say. The best way to find out how many words you actually use would be to carry a recording device during a normal week and then transcribe it to create your own corpus, together with everything you’ve written during the same time. (If you do this, please email us and share your results!)

In day-to-day use, if we’re talking about English, it’s probably enough to know just a couple of thousand words actively. In other languages, a fewer number of words may be enough, depending on, again, what we mean by “a word,” but also the morpheme-to-word-ratio of the given language: how much information can a single word hold? (Compare the Spanish regresarán to the English translation “they will be back.”) Regardless, a couple of thousand words is good news for any language learner! If you learn the most frequent words, you have the tools you need to get around in everyday situations. You don’t have to know “keyboard,” the 5,107th most common English word (according to this brilliant resource based on the British National Corpus) when instead you can say “that thing on a computer with, kind of, “letter-buttons” where you type words, you know, what is it called?” This is how all non-native speakers get by, at more or less all proficiency levels!

However, if you want to read a book or watch a movie, you’ll need to know a few thousand more words, depending on the genre. You don’t have to be able to actively use all the words you read and see, though. There is your active vocabulary, which are the words you use, and then there is your passive vocabulary, consisting of words you recognize and know the meaning of but don’t (yet) use. Also, most of the times when reading or listening, it’s fine to not understand 100 percent of the words — you get them from context.

The number of unique words used is also very different in different types, or shall we say manifestations, of language. A 100-word text message to a friend about meeting up for dinner is likely to only pull from the 1,000 most common words, except for some specifics like vegetarian or Vietnamese. When randomly picking the first paragraph of a bunch of articles in a daily newspaper though, we’ll find that 20 to 50 percent of all words fall outside of the top thousand list. There is an online tool you can use to try to write a text using only the top thousand words — a glimpse into how it feels to be a beginner-level second language learner!

Which Type Of Vocabulary Do You Need?

We’ve established that we need only a fraction of all the words in a dictionary to speak a language. But to what extent can a frequency list of words in a language really help a striving learner? While it’s definitely smart to focus your learning on the most common words, it can also make your learning feel a little…contextless. Very basic example: you would want to learn how to say hello, but “hello” in the English BNC corpus isn’t even among the top 2,000. And while “banana” is a word that every two-year-old and most beginner-level learners know, it’s only as frequent in the corpus as legislature, monastery and aviation.

It all really comes down to being able to describe your world and your needs. That’s also why a 10-year old and an advanced non-native English speaker may have the same vocabulary size (about 10,000), but very different words in it. There are so many everyday objects and concepts that are abundant in a child’s world that would never show up in an L2 speaker’s world, and hence they never have to learn them. Names of flowers, household items, bodily functions, illnesses, to name a few. Depending on the kid in question, they probably also know words for car parts, unusual animals, medieval weapons, outer-space warfare, makeup or food that a non-native English speaker doesn’t. Not to mention all that tweenie slang.

It can certainly be frustrating. Everyone learning a second language has at one point stared angrily at a child, thinking, “You can’t even blow your nose, but you speak fluently the language I’ve been trying to learn for years.” However, it could very well be that you have the exact same vocabulary size, but that it covers different areas. They know pliers, ladle and colander, you know fiscal, platonic and altruism. One advantage you have as an adult language learner is that you already know a lot of cognates in your own language, so focusing your vocabulary acquisition on so-called internationalisms can do wonders for your vocabulary in no time. 

What Vocabulary Size Does It Take To Be Fluent?

Vocabulary size doesn’t say that much about your fluency. It’s far from a precise measurement of language skills, and we need to view the concept of fluency as the ability to communicate and handle most situations successfully in the language. This, too, is a definition to take with a grain of salt: we can all think of a number of unsuccessful communications we’ve found ourselves in, in our native tongue.

The vocab needed for successful communication is highly dependent on the situation. Are you working in the language you’re learning? Congratulations, you now have to learn words like actionable or leverage. Are you learning a new language to speak to your partner’s family at dinner? Then you might need words for food, household items or family relations. The good thing is that it will all sort itself out! You’ll first learn the building blocks and words you need for basic communication, and the rest will follow until the day you’re just not being braggadocio about your huge vocabulary, but actually communicating successfully.

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