The Uses and Abuses of Disfluencies

An essay on the identification of “avoidance disfluencies” in people who stutter

By Paul Brocklehurst PhD.

Director of The Stammering Self-Empowerment Programme

You can download a printable PDF version of this file here


Strictly speaking, many of the abnormal disfluencies produced by people who stutter are not primary symptoms of stuttering[1]. On the contrary, they are actually subtle avoidance behaviors that we have learned to employ in order to avoid stuttering.   I call such disfluencies “avoidance disfluencies”, and unlike “stuttered disfluencies” (the primary symptoms of stuttering) we do have some direct control over whether or not we produce them. In this essay I shall explain why, in order to successfully manage stuttering and achieve a more optimal level of communication, we need to be able to identify and, as far as possible, eliminate these avoidance disfluencies from our speech.  This is no easy task, because many avoidance disfluencies sound identical to the “normal disfluencies” that are produced by speakers (both stutterers and non-stutterers alike) when trying to formulate what they want to say. However, whereas normal disfluencies play an important role in facilitating successful communication, the net effect of avoidance disfluencies is entirely negative, not least because they sustain or even increase our fear of stuttering and prevent us from learning to cope with stuttering in an adaptive way.

In this essay I explain in detail the differences between normal disfluencies and avoidance disfluencies and precisely why normal disfluencies are beneficial and avoidance disfluencies are harmful.  I then discuss my experiences of trying to eliminate avoidance disfluencies from my own speech, and also of trying to help clients who stutter to eliminate them from their speech.

Distinguishing between normal and avoidance disfluencies

As mentioned in the introduction, to an outside listener, avoidance disfluencies may sound identical to normal disfluencies, and in many cases it is impossible for listeners to distinguish between the two.  The difference between these two types of disfluency lies not so much in their form (i.e. in what they sound like), as in the reasons why they occur. Essentially, speakers produce normal disfluencies when they experience slowness or difficulty formulating the words they want to say, such that, when an appropriate moment comes to speak, they find themselves not ready, and therefore unable to proceed. Thus the most basic sort of normal disfluency is a silent (i.e. unfilled) pause that continues on a little longer than it should. Listeners are likely to perceive such pauses as hesitations. Because such silent pauses pose opportunities for other people to butt in, speakers frequently fill them with some sort of noise. The presence of “filled pauses” signals to listeners that the speaker is still trying to speak, and in so doing, it helps to buy some extra time for the speaker to complete the formulation of what he wants to say. So, for example, rather than remaining silent, speakers may repeat or prolong some of their previous sounds or words (sometimes also substituting some of the sounds or words with more appropriate ones), or they may utter some special “filler” words, or phrases, to fill the gap until they have formulated what they want to say and are ready to continue on. Essentially, all of these normal disfluencies are stalling strategies that speakers normally adopt when they find that they are a bit slow at formulating what they want to say.  

Exactly the same range of stalling strategies that constitute normal disfluencies can also be used as Avoidance disfluencies to avoid stuttering. That’s why it’s so hard for listeners to tell the difference between the two. However, unlike normal disfluencies, avoidance disfluencies are produced exclusively by people who stutter. We produce them when, despite knowing exactly what words we want to say, we anticipate that we will stutter and that the words will not come out in the way we want. So, instead of continuing on and risking the possibility of stuttering we start producing these disfluencies as a delaying tactic in the hope that, if we delay the feared sound or word long enough, we may not stutter on it after all.

Both types of disfluency (i.e. both normal and avoidance disfluencies) involve exactly the same stalling strategies, and exactly the same range of disfluency options (silent pauses, filled pauses, repetitions etc.) is available to speakers engaging in avoidance disfluencies as is available to speakers engaging in normal disfluencies. However, whereas normal disfluencies are the symptoms of stalling in order to complete the sentence formulation, avoidance disfluencies are the symptoms of stalling in order to avoid stuttering. Importantly, speakers are not trying to avoid anything when they produce normal disfluencies.  On the contrary, they are busy formulating what they want to say[2].

Normal disfluencies fulfill important communicative functions

Bearing in mind how difficult it is to distinguish between normal disfluencies and avoidance disfluencies, you may wonder whether it would be easier simply to stop producing both forms of disfluency. The reason why this is not a feasible option is because normal disfluencies fulfill some important functions and are necessary for successful communication.  Research into the role of normal disfluencies in communication has repeatedly found that speech that is devoid of such disfluencies is harder for listeners to pay attention to, harder to understand, and harder to remember.  Research has revealed that normal disfluencies orient the listeners’ attention and alert them to the likelihood that the speaker is about to say something difficult or unusual. This heightened attention causes listeners to focus strongly on the words immediately following the disfluency. Normal disfluencies also slow down the rate at which a speaker can deliver his message; and, because they tend to occur at points that are critical for understanding the sentence as a whole, the slower rate of delivery at these points provides listeners with exactly the extra time they need in order to process what they have heard.

The majority of research into the roles of normal disfluencies has focused on filled pauses such as ums, uhs and ers[3]. Although some researchers have found minor differences in the effects of different types of filler, it seems likely that all forms of normal disfluency have much the same positive effects on listeners’ attention and on their comprehension and retention in memory of words and information that immediately follow such disfluencies. The one notable exception to this is silent pauses. Although in monologues, for example, when preaching or delivering a speech, silent pauses can be used to great effect[4], in conversational settings listeners often perceive silent pauses as opportunities to steal the floor – to butt in and start talking. This is especially likely to happen if a child or a speaker of low social standing produces silent pauses, and it is also especially likely to happen when speaking over the telephone (because the listener may not realize that the speaker is still trying to speak). Consequently, in conversational settings, silent pauses tend to reduce the speaker’s communicative effectiveness, whereas filled pauses tend to enhance it.

The misuse of disfluencies by people who stutter

Although they may not be consciously aware of it, speakers (both stutterers and normally-fluent speakers) learn early in their childhood that filled disfluencies (including repetitions, prolongations and interjections) all help to hold the listeners’ attention and can be used as stalling strategies to hold the floor and buy some much needed extra time while trying to formulate what they want to say. The use of these filled disfluencies quickly develops into a habit and speakers soon find themselves producing them automatically, without making conscious effort to do so. This behavior is absolutely normal and completely fine while experiencing formulation difficulty. However, using filled disfluencies (or for that matter even silent pauses) to maintain listeners’ attention while we try to avoid anticipated stuttering is not beneficial. On the contrary, it is positively detrimental.  I will clarify the reasons below.

Why using avoidance disfluencies in response to the anticipation of stuttering is unhelpful

If we anticipate that we will stutter on a word and, as a result, we employ one or other of the forms of avoidance disfluency described above, sometimes we will find that, when we come to attempt the feared word, we do not stutter on it after all. Each time this happens, it feels like the avoidance disfluency has worked and we have successfully avoided stuttering. Consequently our tendency to produce avoidance disfluencies before feared words is reinforced, and becomes a habit. However, stalling (or rushing ahead) before feared words does not always enable us to avoid stuttering on the feared word. When it doesn’t work, it adds to the problem because, at such times, instead of simply getting stuck on a feared word in a straightforward way, we now become disfluent before the feared word and then get stuck on it as well.  In this way, the avoidance disfluencies we habitually use to avoid stuttering themselves become secondary symptoms of stuttering.  

Also, there is a further problem with using avoidance disfluencies before feared words…  Although we often correctly anticipate when we will stutter, we don’t always get it right. Research into the anticipation of stuttering has shown that people who stutter in fact experience many false alarms – instances when, after anticipating that they will stutter, they do not stutter after all. Indeed, research on children who stutter (who have not yet developed the tendency to use avoidance disfluencies before anticipated stutters) suggests that these false alarms happen regularly.

Importantly if, in our desire to avoid stuttering, we  use avoidance disfluencies every single time we anticipate that we will stutter, we never give ourselves the chance to find out whether or not we would really have stuttered had we not used them. As a result we are very likely to develop the false belief that… “if we don’t use avoidance disfluencies when we anticipate stuttering, we will definitely stutter”.

The benefits of acceptance of stuttering and of a pragmatic attitude towards disfluencies.

Probably one of the main reasons why people who stutter start to produce avoidance disfluencies when they anticipate upcoming stuttering is because stuttering is not a pleasant experience.  It is something most of us would rather avoid if we possibly could. So, as long as we harbor the belief, or hope that, by producing avoidance disfluencies, we can avoid stuttering, the temptation to try to do so will be difficult to resist. One way through this dilemma is to treat stuttered disfluencies (the primary symptoms of stuttering) as if they are essentially unavoidable. If we can consider them in this way, then we will find ourselves more able to simply let them happen. Essentially, if we accept that we cannot avoid them, we are less likely to try to do so. Consequently, we can then focus our attention on finding ways of ensuring that they cause minimum disruption to our flow of speech.  Essentially, I’m suggesting that we can make a sort of trade-off. By accepting the inevitability of our stuttered disfluencies, we can stop producing avoidance disfluencies, and in so doing, overall our speech becomes less disfluent than it otherwise would be and our ability to successfully get our messages across to the listener is increased. Of course, this is a compromise, because we are still stuttering. In order to be able to make this compromise, we have to accept our stuttering and not try to hide it. In this respect we need to be pragmatic.

Having allowed a stutter to happen, and accepted that we simply can’t say all the sounds we want to say, the pressing issue that then arises is “How can we best get the message across? ” I don’t believe there is just one right answer to this question, and it may be that different people find different ways that work for them. So, bearing this in mind, In the following section I shall describe my personal experience of what has worked for me.  

Getting the message across - Personal experiences

I first made a firm commitment to stopping myself from producing avoidance disfluencies back in 2000. Since then, I have experimented with a number of ways of getting my messages across to listeners when I find myself blocking on a sound or word. Of these, by far the easiest and generally most successful method – and the one that I now use as my default method – is to simply skip the sound or word I can’t say and get on with saying the remainder of the words that I can say. I should stress here that I don’t mean avoiding the sound or word I can’t say. On the contrary, I always try to say the sound once. But then, if I find I can’t say it more or less straight away, I abandon it and carry on with the rest of the sentence. To my mind, this is a highly pragmatic approach insofar as it ensures that I say what I can say with a minimum of delay because I don’t waste time continuing to try to say the sounds I can’t say.  It does not involve any avoidance, yet it does involve acceptance.  More often than not, I find that the listener is able to guess any sounds that I abandoned, from the context in which I have said them, and so he or she gets the message without me needing to go to any extra lengths to convey it. So, jumping over the problem sounds in this way is always my first strategy. Sometimes it doesn’t work and, despite continuing on to the end of what I want to say, I become aware that the listener has not been able to understand me. If this is clearly the case, I may go back and try to say the entire phrase again, or I might find a way of rephrasing it, or I might write it down, or I might simply accept defeat and give up. But whatever I do, I maintain two golden rules: never use avoidance disfluencies, and never use force. By “never use force”, I mean if I find myself blocking on a sound I never try to push through it. If a sound won’t come out of its own accord, I simply skip it and continue on with the rest of the sounds and words that will come out. Furthermore, just as I take care not to stall before an anticipated stutter, I also take care not to speed up either, as this too is a form of avoidance disfluency.

As mentioned, I first started employing this approach back in the year 2000. Before that, I had always stalled before anticipated blocks and then continued to try to say the sounds and words I was blocking on until I felt satisfied that I had said them well enough. This sometimes resulted in long delays, and these delays fuelled my fear of blocking. In the beginning, giving up on the sounds I was blocking on felt very strange, but when I did give up I immediately found that doing so enabled me to continue on with the rest of what I wanted to say without any form of struggle. My fear of blocking diminished immediately, and the tendency to block also diminished substantially. This worked very well in most speaking situations, although I continued to experience difficulty in situations where it was essential to articulate specific sounds clearly in order for the listener to understand what I was trying to say. Overall, however, adopting this approach coincided with an immediate and sustained reduction in my tendency to block and in my fear of blocking. Over the years, since adopting it, this has generalized to the point where the situations that I initially continued to experience some difficulty with are now no longer difficult for me.

Over the past two years I have been developing a form of therapy technique based upon the understanding of disfluencies that I have outlined in this essay. I have called this technique “The Jump”. I intend to continue posting details of this technique as evidence of its effectiveness (or not) continues to emerge.  However, one finding that has already become very clear is that although many of the more blatant avoidance disfluencies produced by people who stutter are easy for listeners to recognize, the more subtle ones can only be reliably recognized by the stutterers themselves. From the listener’s perspective it is often impossible to distinguish them from normal disfluencies.  The implication of this is that clinicians can only help to a limited extent in the task of identification of avoidance disfluencies. So, ultimately, success in this approach to therapy is only possible if clients themselves are able to distinguish between these two forms of disfluency. My experience with clients so far suggests that this is not always an easy task. This is especially the case for the clients I have seen who, in addition to stuttering, frequently also experience sentence formulation difficulties or word-finding difficulties. It seems that, in those individuals, stuttering (and the anticipation of stuttering) is often itself triggered by those difficulties.


In this essay I have noted that not all of the abnormal disfluencies produced by people who stutter are primary symptoms of stuttering. On the contrary, many are actually manifestations of our attempts to avoid stuttering. Although these “avoidance disfluencies” may sometimes appear to help, in the long run they actually make stuttering worse, and people who stutter would be better off if they stopped producing them. The difficulty, which it comes to stopping them, is in being able to distinguish between avoidance disfluencies – which are detrimental, and normal disfluencies – which positively help us get our messages across. The main body of this essay provides detailed explanation of how to go about differentiating these two types of disfluency. Ultimately, only stutterers themselves can know which is which. Having learned how to recognize avoidance disfluencies, the key to being able to stop producing them is to stop trying to avoid stuttering and to focus instead on minimizing the delay that stuttering causes to getting ones’ message across. To make these changes, it is helpful to adopt the attitude that stuttering is essentially unavoidable and instead of continuing trying to say sounds and words that we can’t say, simply to get on with saying the remaining words that we can say.

Further reading on the effects of normal disfluencies on listeners.

Arnold, J. E., Kam, C. L. H., & Tanenhaus, M. K. (2007). If you say thee uh you are describing something hard: The on-line attribution of disfluency during reference comprehension. Journal of Experimental Psychology: Learning, Memory, and Cognition, 33(5), 914-930.

Brennan, S. E., & Schober, M. F. (2001). How listeners compensate for disfluencies in spontaneous speech. Journal of Memory and language, 44(2), 274-296.

Brennan, S. E., & Williams, M. (1995). The Feeling of Another s Knowing: Prosody and Filled Pauses as Cues to Listeners about the Metacognitive States of Speakers. Journal of Memory and language, 34(3), 383-398.

Christenfeld, N., & Creager, B. (1996). Anxiety, alcohol, aphasia, and ums. Journal of personality and social psychology, 70(3), 451.

Collard, P., Corley, M., MacGregor, L. J., & Donaldson, D. I. (2008). Attention orienting effects of hesitations in speech: Evidence from ERPs. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34(3), 696-702.

Corley, M., MacGregor, L. J., & Donaldson, D. I. (2007). It’s the way that you, er, say it: Hesitations in speech affect language comprehension. Cognition, 105(3), 658-668.

Corley, M., & Stewart, O. W. (2008). Hesitation disfluencies in spontaneous speech: The meaning of um. Language and Linguistics Compass, 2(4), 589-602.

FoxTree, J. E. (2001). Listeners' uses of um and uh in speech comprehension. Memory & cognition, 29(2), 320-326.

Kasl, S. V., & Mahl, G. F. (1965). Relationship of disturbances and hesitations in spontaneous speech to anxiety. Journal of personality and social psychology, 1(5), 425.

Mahl, G. F. (1956). Disturbances and silences in the patient's speech in psychotherapy. The Journal of Abnormal and Social Psychology, 53(1), 1-15.

Schachter, S., Christenfeld, N., Ravina, B., & Bilous, F. (1991). Speech disfluency and the structure of knowledge. Journal of personality and social psychology, 60(3), 362-367.

Smith, V. L., & Clark, H. H. (1993). On the course of answering questions. Journal of Memory and language, 32(1), 25-38.

[1] That is to say they are not primary symptoms of stuttering. However, they could be classified as secondary symptoms of stuttering.

[2] Although most avoidance dysfluencies involve slowing down (stalling) before feared words, some people who stutter develop the habit of speeding up before feared words. This is also a form of avoidance dysfluency. The symptoms produced as a result are less likely to be mistaken for normal dysfluencies, but may resemble cluttering.

[3] See the bibliography at the end of this essay for further reading on this topic.

[4] Martin Luther King’s famous “I have a dream” speech provides a good example of the power that silent pauses can have when skillfully used.