13 February 2024

How Many Words Do You Need to Know in a Second Language?

slender hands on a desk with a cup of coffee and a notebook

As an adult, learning a second language is an entirely different experience to learning your first, native language – or ‘mother tongue’ – as a child. When you are developing your native language skills in childhood, you happen to be learning all sorts of new things – how to crawl and walk, what different foods taste like, where you live, what the plants and animals around you are – and these experiences all enrich your evolving experience of life. Everything you encounter presents you with an opportunity to learn something new, and language gives you one way of labelling and understanding new objects, people and places.  

By the time you have grown up and are living in the adult world, you already have a deep understanding of the world, and the new things you continue to learn slot into your existing understanding of the context of your life – the people, the places, the objects, the food… you name it. Instead of learning what these things are in the first place, learning a second language gives you another set of ways to name them – so language acquisition is a process of translation from one word to another (in a second language), rather than translating an understanding of an object or concept into language for the first time (into your native language). It is like you are adding another layer of understanding onto your world when you learn a second language. 

But how many words need to fit into this layer for you to have sufficient words to be able to ‘get by’ in your second language? That is the question we try to answer in this article. 

What Is In a Word? 

Native speakers are thought to know between 15,000 and 20,000 word families (for example, the word ‘run’ and all its forms counts as one word family), but we probably do not need anywhere near that number of words (or word families!) to hold a conversation in a second language. But where do you begin when you want to accumulate a sufficient number of  useful words in a new language? 

When you learn a new language, you ideally start with some of the most useful things to know – how to say hello and goodbye, how to ask if someone speaks English, and the words for common places, times, shapes and colours. Usefulness is the key – and learning with a particular purpose in mind (such as business) may also influence the words you aim to learn and use as your knowledge grows.  

Some words are certainly more useful than others. Imagine that you have learned 1,000 words of a new language, but half of those bear a close relation to some of the other words you know – perhaps you know the words for several different shades of green, but you cannot recall how to ask for directions or check the time. How helpful would that be?  

In the same vein, what counts as a word? Imagine you have learned all the different verb forms for a handful of seemingly essential words, but you cannot put these to good use in a conversation. How helpful are all these words – and should several different forms of a headword such as ‘walk’ or ‘eat’ count as one word or many?  

Without some strategic planning, your 1,000 words could look quite different to somebody else’s – and lead to quite different levels of useful comprehension.  

‘Getting By’ in a New Language 

When you get started with a new language, it may help to think about why you are learning the language in the first place. If it is for work, you may find that a little goes a long way at first, especially if the same topics keep coming up in relation to your business (if, for example, you work in manufacturing, you may need a different set of work-related words than someone who works in healthcare).  

Stuart Webb, a professor of applied linguistics, suggests that you can understand around 75% of spoken English if you learn only 800 of the most common word families used in English. Further, he says that learning between 800 and 1,000 of the most common word families should be enough to help you quickly pick up the basics of a new language. A handful of words can go further than you expect! 

If you can hold a conversation in your second language, maybe you already have enough words for your purposes – and being able to talk with confidence on a few key topics is an excellent way to impress your business partners and build rapport. However, a personable business contact will also appreciate the effort you are making to engage in a common language, so any progress is good progress and should be welcomed.  

With practice, you can expect to naturally expand your skillset over time. Language learning is an ongoing journey – and though it may seem tough at times, it is an amazing reward to be able to deepen your understanding of the world and its layers through developing your knowledge of a new language. 


To start your second language learning journey, please do get in touch. We offer bespoke training for individuals, groups and businesses, and we can offer language support in over 70 languages. 



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