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What is Fluency?

Know what it is, so you can improve it

What’s fluency and what does it mean to be “fluent” in a language?

Different people have different answers to this question.

One might say, “You’re fluent when you’re able to speak smoothly, not like a broken robot.” 

Another person might say, “Fluency is all about having a wide vocabulary. Your speech will flow and you’ll sound fluent if you know a lot of words.” 

A teacher, on the other hand, might tell you that fluency is related to “using language naturally”.

You too have your own unique idea of fluency. Maybe you think it’s the ability to speak about anything without thinking about grammar.

I asked a new online friend I’ve recently made, ChatGPT, what it thinks about fluency. 

It told me this:

ChatGPT answer to the question What does it mean to be “fluent” in a language?

Fluency is indeed a concept that is difficult to pin down. In the language teaching literature, this complex notion has been defined and explained in different ways by different linguists. 

Let’s take a look at what the experts say so we can get an insight into what being fluent involves.

Different definitions of fluency

Image of a book "From the real experts"
Photo by Rita Morais on Unsplash

 Thornbury (2005) says that fluency depends on:

  • how often you pause when you speak.
  • how long your pauses are.
  • where those pauses occur in your speech.
  • whether or not you fill the pauses.

Imagine saying, “I am…a….a……[pause]…erm….a teacher, and……erm….I [5-second pause] live….[long pause]….in Italy.”

You’ve paused too often and for too long. Those breaks occur in places where the listener wouldn’t expect them. The sentence “I’m a teacher,” for example, should normally come out of your mouth as a single unit, not with pauses between the words. 

Also, you didn’t fill the 5-second pause. You could have said, “I can’t remember the right verb. Erm…wait a second, oh yes, live! I live in Italy.”

So, according to Thornbury’s definition, you wouldn’t be considered a fluent speaker.

Another expert, Hughes (2006), says that fluency depends on how much you consciously focus your attention on the elements of speech (grammar, vocabulary, structures, etc.) when you communicate.

For example, if you need to think too much about how to build a sentence or what verb form you should use, you’re highly likely to break the flow of your speech. 

You would, once again, fail the fluency test.

Two language researchers, Conti and Smith (2016), give us another perspective. They suggest that fluency is about how quickly you can retrieve words, structures and expressions from your long-term memory.

You might have learned a lot of words. They’re all in your brain. How long does it take you to find and use them while you’re speaking? Too long? If so, you won’t sound fluent.

But what about fluent speakers? What makes them fluent?

What do fluent speakers do?

According to the Analytic Descriptors of Spoken Language provided by the Council of Europe, C2 speakers – highly proficient users of the language – are considered fluent because they can express themselves:

  • spontaneously.
  • at length.
  • with a natural colloquial flow.
  • avoiding or backtracking around difficulty so smoothly that the interlocutor is hardly aware of it.

(Council of Europe, 2001:28).

In other words, you’re fluent if you can speak naturally, for long periods of time, and without needing to think about how to say what you want to say. If you encounter difficulties (e.g. you can’t remember a word) the person you’re talking to might not even notice that you’re struggling.  

This description is especially useful as it doesn’t simply describe a speaker’s speech, but also a listener’s perception of it. In fact, you might sound fluent to the ears of one listener, but not to those of another. This is why fluency is hard to test and measure objectively.

So, how can we best define fluency? If we know exactly what it is, we can then take action and work on it to become more fluent.

Let me share my favorite definition of fluency. 

My favorite definition of fluency

I believe this is the most accurate description of what fluency is: 

Fluency is the ability to “[make] the best use of what is already known” (Nation, 2014:11).

I love this definition. 9 clear and simple words that tell us a lot about the nature of this complex concept.

You’re fluent when you’re able to use your existing linguistic resources effectively, no matter how limited these might be.

Existing linguistic resources = language items, grammar, and vocabulary you have already learned.

Effectively = naturally, spontaneously, at length, without pausing too much, without causing misunderstanding, and so forth.

So, it doesn’t matter how many words you know. 

You might be a beginner speaker but you can still be fluent (think kids). You might know thousands of words, but if you can’t remember them or need to pause because you’re unsure which one to use,  your degree of fluency will decrease.

This definition, therefore, tells you exactly how you can develop your fluency.

Image of words
Photo by Glen Carrie on Unsplash


How can this definition of fluency help you become more fluent?

You may think you need to have a bigger vocabulary or learn more grammar and idioms to sound fluent. No. You just need to make the best use of what you’ve already worked hard to learn.

So if you want to improve your fluency, practice using what you already know. It’s as simple as that.

Vague, I know. But there are fluency activities you can do and I’ll talk about these in my next post.

I hope this is helpful. 



  • Council of Europe. (2001). Common European Framework of Reference for Languages: Learning, teaching, assessment. Cambridge: Cambridge University Express.
  • Hughes, R. (2006). Spoken English, TESOL and Applied Linguistics: Challenges for Theory and Practice. New York: Palgrave Macmillan.
  • Nation, P. (2014). Developing fluency. In T. Muller, J. Adamson, P. Brown, & S. Herder, Exploring EFL Fluency in Asia (pp. 11-25). London: Palgrave Macmillan.
  • Smith, S., & Conti, G. (2016). The Language Teacher Toolkit. CreateSpace Independent Publishing Platform
  • Thornbury, S. (2005). How to Teach Speaking. Harlow: Pearson Education Limited. 

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