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Childhood Fluency Disorders

The scope of this page includes stuttering and cluttering in preschool and school-age children.  A Portal Page on adult fluency disorders will be developed in the future.

Fluency is the aspect of speech production that refers to continuity, smoothness, rate, and effort. Stuttering, the most common fluency disorder, is an interruption in the flow of speaking characterized by repetitions (sounds, syllables, words, phrases), sound prolongations, blocks, interjections, and revisions, which may affect the rate and rhythm of speech. These disfluencies may be accompanied by physical tension, negative reactions, secondary behaviors, and avoidance of sounds, words, or speaking situations (ASHA, 1993; Yaruss, 1998; Yaruss, 2004). Cluttering, another fluency disorder, is characterized by a perceived rapid and/or irregular speech rate, which results in breakdowns in speech clarity and/or fluency (St. Louis & Schulte, 2011).


Stuttering typically has its origins in childhood. Most children who stutter, begin to do so around 2 ½ years of age (e.g., Mansson, 2007; Yairi & Ambrose, 2005; Yaruss, LaSalle, & Conture, 1998). Approximately 95% of children who stutter start to do so before the age of 5 years (Yairi & Ambrose, 2005).

All speakers produce disfluencies, which may include hesitations, such as silent pauses, and interjections of word fillers (e.g., "The color is like red") and nonword fillers (e.g., "The color is uh red"). Other examples include whole-word repetitions (e.g., "But-but I don't want to go") and phrase repetitions or revisions (e.g., "This is a- this is a problem"). These are generally considered to be nonstuttered (typical) disfluencies (Ambrose & Yairi, 1999; Tumanova, Conture, Lambert, & Walden, 2014). When a child uses a high number of nonstuttered (typical) disfluencies, differential diagnosis is critical to distinguish between stuttering, avoidance, and a language disorder.

Less typical, stuttering-like disfluencies (Yairi, 2007) include part-word or sound/syllable repetitions (e.g., "Look at the b-b-baby"), prolongations (e.g., "Ssssssssometimes we stay home"), and blocks (i.e., inaudible or silent fixations or inability to initiate sounds). In addition, compared with typical disfluencies, stuttering-like disfluencies are usually accompanied by greater than average duration, effort, tension, or struggle. Aspects that factor into perception of severity include frequency and type of stuttering and the ability of the person who stutters to communicate effectively.

Some young children go through a period of excessive disfluency, which does not persist for a large majority of these children. Estimates of remission vary from 6.3% (Reilly et al., 2013) to 47% (Fritzell, 1976) to 89% (Yairi & Ambrose, 1992, 1999; Yairi, Ambrose, Paden, & Throneburg, 1996). The large variability in recovery estimates may be due to factors such as the way the data were collected (e.g., individual, clinic, or community) and the age at which recovery was determined (Reilly et al., 2013).

Stuttering can greatly interfere with school, work, or social interactions (Yaruss & Quesal, 2004). Children who stutter may report fear or anxiety about speaking and frustration or embarrassment with the time and effort required to speak (Ezrati-Vinacour, Platzky, & Yairi, 2001). Children who stutter may also be at risk for experiencing bullying (Blood & Blood, 2004; Davis, Howell, & Cooke, 2002; Langevin, Bortnick, Hammer, & Wiebe, 1998).

Stuttering can co-occur with other disorders, such as speech sound disorders (St. Louis & Hinzman, 1988; Wolk, Edwards, & Conture, 1993); intellectual disabilities (Healey, Reid, & Donaher, 2005); and language disorders (Ntourou, Conture, & Lipsey, 2011). For example, although there is little systematic evidence describing disfluency in autism spectrum disorder (ASD), increasing numbers of case reports indicate both stuttering-like disfluency and non-stuttered (typical) disfluency (Scaler Scott, Tetnowski, Flaitz, & Yaruss, 2014) and atypical disfluency that is additionally distinguished by unusual features, such as repetition of final segments of words (Paul et al., 2005; Shriberg et al., 2001; Sisskin & Wasilus, 2014).


In cluttering, the breakdowns in clarity that accompany a perceived rapid and/or irregular speech rate are often characterized by deletion and/or collapsing of syllables (e.g., "I wanwatevision") and/or omission of word endings (e.g., "Turn the televisoff"). The breakdowns in fluency are often characterized by more typical disfluencies (e.g., revisions, interjections) and/or pauses in places in sentences not expected grammatically, such as "I will go to the/store and buy apples" (St. Louis & Schulte, 2011).

Although the current criteria for cluttering include only symptoms of speech rate and fluency, other disorders may co-occur. For example, there is documentation of cluttered speech in children with learning disabilities (Wiig & Semel, 1984), auditory processing disorders (Molt, 1996), Tourette's syndrome (see Van Borsel, 2011, for review), autism (see Scaler Scott, 2011, for review), word finding/language organization issues (Myers, 1992) and attention deficit hyperactivity disorder (ADHD; Alm, 2011). These disorders (and their features) may occur in addition to a diagnosis of cluttering (or stuttering), and cluttering has been documented with none of these additional features or diagnoses.

A disorder that can be seen as a consequence of cluttering is that of pragmatic disorder; individuals with cluttering may not attempt to repair breakdowns in communication, which may result in less than effective social interaction (Teigland, 1996).

See the Fluency (Children) Evidence Map for summaries of the available research on this topic.

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