CONTENTS:      The development of fluency

                             The onset of stuttering

                             Differential diagnosis between stuttering and normal-


                             The relationship between language development and


                             Models of development: historical and current




Students should be able to:

Present factual information about onset and development to clients

Consider the controversies about how stuttering develops, especially describing the relationship between normal non fluency and stuttering and relating this to differential diagnosis

Make a tentative diagnosis between stuttering and normal non-fluency

Be aware of the current views about predicting persistent stuttering

Begin to consider the relationship between language and stuttering

Compare, contrast and critically evaluate the various models of stuttering development



The development of fluency


The development of fluency entails periods of disfluency. Starkweather (1987) describes this in terms of continuity, rate, rhythm and effort of speech production and there is a research focus on the acoustic phonetic properties (Dalton & Hardcastle 1989).  Yairi (1981) describes how the amount and frequency of disfluencies decreases in the pre-school years (see end for summary of literature by Starkweather 1987).

Between approximately 18 m and 4 years “normal” disfluencies (known as normal-non-fluency (NNF) can increase markedly and cause parents’ anxiety. This disfluency is temporary but is often very difficult to differentiate from early stuttering leading to controversies about management (see below).  Nelson (1985) proposes that a reason for NNF may be that between the ages of 2 and 4, children are learning new words and linking them together in sentences. They are also learning to ask questions requiring different word order.






The onset of stuttering


Historically, stuttering was always thought to develop gradually and with no particular surrounding circumstances of note. Early symptoms were also always thought to be those such as ‘easy’ repetitions, no tension, lack of awareness etc. It was also thought to progress in a relatively linear and uniform way developing in severity as time went on.  The reasons for this set of beliefs are probably because learning theory was used to understand stuttering for many years and as Wingate (76) said “if stuttering is learned then it must be continuously reinforced, grow and perpetuated”.

This model has been and is being challenged by data obtained from the Illinois Stuttering Research Project who have being investigating 150 children over several years (Yairi 83, Yairi & Ambrose 92, 2000). The data shows that:

·        most onset occurs between 24 - 36 months (6 - 12 months earlier that what was thought)

·        stuttering begins suddenly in one third of the children

·        for many stuttering began severely, accompanied by tension

·        in about half, the onset occurred at a time of physical or emotional stress

·        the dysfluency in children suspected of stuttering is different from normal non fluency

·        awareness of stuttering and emotional reaction might begin early in a large number of the children

·        the developmental course takes diverse forms and in fact, rather than growing in severity a large number of the children’s stuttering disappears without intervention.


On the whole, it is often found that onset is hard to determine because a) it might have been present before parents noticed and b) hard to remember actual dates (Onslow, 1993). Another problem dating onset is that many families see their GP first who quotes rather questionable spontaneous recovery figures and tells them their child will "grow out of it". By the time the child does see a speech and language therapist stuttering may be well established. Gottwald and Starkweather (1984) state that because the problem can often be prevented by early intervention, "it seems that much stuttering is caused by the advice given out by misinformed paediatricians". We are also unsure whether it is NNF.


Finally, when onset occurs in adults, it is usually sudden and follows head injury or stroke. Rosenbek (1984) feels that this neurological stuttering is related to motor problems of a dyspraxic nature. In some cases it may be the re-emergence of a childhood problem precipitated by trauma, while in others the individual can have been concealing the problem all his life but following trauma, has less control and it reappears.


Differential diagnosis between stuttering and normal-non fluency (nnf)


For many years there has been a great deal of controversy about this differential diagnosis and

controversies include

·        Does stuttering develop from normal nonfluencies under adverse conditions  (Johnson 1950’s)?

·         are what appear to be normal nonfluencies in some children in fact early stuttering behaviour (Bloodstein 1970 in his continuity hypothesis)?  or

·        is stuttering an entity distinct from NNF?


i.e. are differences between the two quantitative or qualitative)?


Furthermore, should therapists adopt the wait and see approach (some waiting up to a year) or should intervention begin immediately?  Although some research states that 80% of nonfluent children  will achieve normal fluency without intervention (Sheehan & Martyn 1967), research points out that the sooner a problem and its contributing factors is identified, the greater are the chances of success (Williams 1971, Cooper 1976, Shine 1980, Yairi 1992, Onslow 1993).

In other words, clear differential diagnosis has massive implications for treatment and yet it remains really difficult to predict chronicity.


That the two are distinct entities seems to be the more popular view at present but the debate continues. Much current research is devoted to finding predictors of chronicity but, especially where a child has a very borderline profile, the differential diagnosis is not possible.

A number of differentiating factors are suggested to aid diagnosis:



Differences between NNF &  stuttering




·      incipient stuttering has 10+ dysfluencies/100words

NNF has 9 or less/100words (Adams 1977)

·      incipient stuttering - 3+ within word dysfluencies. / 100 words

(Conture & Caruso 1987)

·      incipient stuttering - 3+ repetitions on part word

NNF - less than 2 on part-word (Adams ‘77

Conture & Caruso ‘87 Gregory & Hill ‘87)




·      type of dysfluencies

Incipient stuttering -part word repetitions & prolongations (Adams’77)

NNF - Whole word or phrase repetitions, interjections, revisions

·      insertion of schwa

done in incipient stuttering

not done by NNF (Adams ‘77 Van Riper ‘82 Gregory & Hill ‘84)

(currently queried as a factor (Howell et al 91)

·      uneven stress & rhythm

present in incipient stuttering

not a problem in NNF (Gregory & Hill 1980)

·      difficulty initiating & sustaining airflow

present in incipient stuttering

not a problem in NNF (Gregory & Hill 1980)

·      body tension & struggle behaviour during speech

increased in incipient stuttering (Gregory & Hill ‘80,

Starkweather ‘87)

brief, effortless disfluencies in NNF (Adams ‘77)

·      parental concern

with or without evidence warrants intervention

(Conture & Caruso ‘87)


Guitar 1998 has guidelines for deciding upon normal disfluency, borderline stuttering, beginning stuttering and intermediate stuttering on pages 206/207.


The main 3 problems as highlighted by all researchers (e.g. Onslow 1993, Hayhow 1983) are a) there is immense variability b) early stuttering tends to be episodic and c) non-stuttering children can display stuttering signs sometimes. Probably the main speech feature is part-word repetitions. Bloodstein (1960) said that "there is a tendency for disfluent children to fragment briefer and briefer units of speech."


Formal assessments to differentiate stuttering from normal non fluency


There are few formal assessments which undertake this and most decisions are made using some or all of the above criteria. One assessment which has been produced is The Stuttering Prediction Instrument (SPI) by Riley and Riley (1981/84). This uses a point system to decide if the disfluency warrants attention and looks at history, reactions to stuttering by both parents and child, part word repetitions, longest prolongations and frequency of stuttered events.


Predicting the persistence of stuttering


As mentioned before, Yairi et al (2000) feel able to identify these differentiating factors and go on to outline  STUTTERING RISK PREDICTION FACTORS:


Primary factors

Dysfluency trends - downwards is positive

Family history - FHP of recovered stuttering indicates this and FHP of persistence indicates a greater chance of this.

Gender - males are higher risk


Secondary factors

Severity - not an indicator in first few months

Duration of stuttering - potential risk if stuttering for more than a year

Phonological skills - persistent stuttering may have more phonological problems but alone these cannot predict outcome

Expressive language - not readily distinguished. Unusual language development in persistent stuttering e.g. some 2 yr olds may show precocious expressive language skills.


Other factors to be considered based on clinical experience:

Concommitant disorders - increase risk

Reactions - presence of emotional reactions in child or parents

Age - onset at an older age is a risk because of the child’s own awareness, listener reactions and environmental demands




Cook & Botterill (2000) present the profile of risk used at the Michael Palin Centre for Stammering Children and which is based on the theoretical framework:

















Physiological - males, positive family history, developing motor skills

Linguistic - history of speech and language problems, nature of dysfluency, child’s awareness and concern

Environmental & Emotional - contradictory evidence but demands and pressures thought to interact.


Howell et al (1995, 2000) examine function word disfluencies as having the role of ‘buying planning time’ in all speakers. Children who do not grow out of their stutter have a different dysfluency pattern i.e. they do not repeat function words but try the ‘difficult’ and ‘unplanned’ content word, now encountering problems here. At this point persistent stuttering is reached.


The relationship between language development and stuttering


In the past it has always been felt that linguistic complexity affects the level of fluency (Brown 1937) so one should always study the child's problem in its linguistic and situational context.


In addition there has also been interest in whether stuttering children have atypical language skills. Bernstein Ratner (1994) summarises research findings where the hypothesis is that particularly children differ in their linguistic abilities from those who speak more fluently (measured by syntactic complexity of spontaneous speech, sentence imitation tasks, standardised tests, vocabulary, oral & written narrative ability and reading). Although the Andrew’s et al review in 1983 noted that children who stutter performed more poorly on some tests they did not differ appreciably. But, as we can see below, clinicians have observed higher than usual incidences of language and/or phonological disturbance in subgroups of stuttering children. Real issues may only be available with hindsight but it is hard to know which comes first, the stutter or the linguistic delay or if the two co-exist as primary conditions.


Wingate (1988) notes that dysfluencies can be both

lexical:                        broken words

                                    prolonged sounds

                                    part-word repetitions

                                    word repetitions

and supralexical:        phrase repetitions



                                     incomplete phrases

and yet almost all the assessment procedures look at the former. This concentration has led to misleading statements about differentiating criteria i.e. omits the prosodic features. For example, there is no reference in an assessment as to whether a word is in an embedded clause, and only the number of words stuttered are counted.


Conture (1982 and ongoing) is especially interested in the relationship between stuttering and disordered phonology finding that more children who stutter have articulation problems than those who don't.


5-7% of non-stutterers in the population have articulation problems.

30-40% of children who stutter have real difficulties with articulation.


He feels that the basic mechanism is an inability to quickly and accurately select and encode sounds either due to a perceived need to do it fast, to increase length and complexity quickly or when state or trait anxiety encourages the speeding up of phonological encoding.




These models look more at the patterns of stuttering development over time rather than focusing on distal (or original) causes. Again there are a number of views which can influence management.


Historical views

a) patterns of stuttering at onset and development are described by Van Riper (1971) in terms of tracks. These are occasionally referred to nowadays but for the most part are felt to be a little rigid and do not account for all the variations in types of stutter. (see hard copy from lecture for summary of tracks).


b)Bloodstein (1960/61) described the development of stuttering in terms of phases. These have similar criticisms as the tracks from Van Riper. (see hard copy from lecture).


c) Wendell Johnson’s semantogenic or diagnosogenic theory stated that the stuttering child is normal in every way except that his normal nonfluencies are evaluated as stuttering by an adult - mostly the mother. The child begins to accept this evaluation and gradually comes to believe that there is something wrong with the way that he speaks. fear, anxiety and guilt become associated with the act of speaking and true stuttering begins as the child starts to perceive himself as a stutterer. A profoundly effective theory but became unpopular when parents started to be blamed for their child’s stuttering.


One of the most thorough studies completed to date into the reasons for the development of stuttering was that by Andrews and Harris in 1964 in Newcastle. They surveyed a population of 7,358 9 - 11 year olds and found 86 children who stuttered. Factors which emerged were a degree of social deprivation in the home, mothers' poor ability to manage, a positive family history of stuttering, a history of poor or late talking in the subjects and poor attainment on tests of intellectual ability. Not all of these would be common to all, but family history, late talking and poor talking were common to many. Their conclusions suggested that stuttering might be of multifactorial inheritance: a genetic loading and unfavourable environment exceeding a certain threshold. They also found that 20% started stuttering on their first words, 35% had some fluent speech prior to starting stuttering, 28% had speech well established until starting stuttering at infant school and 14% had no difficulty until junior school





Current views




This model of stuttering deals with the notion that stuttering children may be responding to different influences. Nine components are envisaged, some being "neurologic" and others being "traditional" which are further subdivided into intra - and inter - personal.














Attending disorders

High self expectations

Disruptive communication environment

Auditory processing disorders

Manipulative stuttering

Unrealistic parental expectations

Sentence formulation disorders


Abnormal parental need for child to stutter

Oral motor disorders










            They make the premise that stuttering occurs when “...disorders in the various components of the child’s system of communication are of sufficient magnitude to reach a critical threshold of fluency breakdown and that different children may be responding to different influences. Their model aims to assist in therapy planning.







There are two premises. First the "growing capacity to talk more easily is paralleled by increasing demands for fluent speech, demands placed on children by the people they communicate with and by themselves. A second premise is that when the child's capacity for fluency exceeds the demands, the child will talk fluently, but when the child lacks the capacity to meet demands for fluency, stuttering, or something like it, will occur." Starkweather (1987). It is when demands for fluency chronically exceed their capacity that stuttering may occur. Patterns of struggle, tension and emotional reaction have become habitual and semiautomatic.





Growth in capacity comes from:

a) Increasing control over movements of the vocal tract. This is by increasing ability to move and react rapidly to stimuli, increasing ability to co-ordinate simultaneous movements of the vocal tract and increasing ability to plan and execute a sequence of movements.

b) the development of a sense of rhythm which allows the child to anticipate the movements of speech production.

Sources of increased demands come from:

a) development of language skill: semantic, syntactic, phonologic and pragmatic

b)  changing expectations of listeners




Wall & Myers (1984/95) propose a three factor model for the assessment and treatment of childhood stuttering. This model serves as a framework for their book and attempts to bridge the gap between theory and therapy. Theories of stuttering and their therapeutic implications are considered within this framework


Psycholinguistic factors                                                                                 Psychosocial factors

Phonology                                                                                            Parents

Syntax                                                                                                  Other significant adults

Semantics/cognition                                                                              Peers

Propositionality of utterance                                                                  Social load of discourse






                                                            Physiological Factors

                                                VOT & VIT

                                                Laryngeal & supralaryngeal tension

                                                sensori motor co-ordination


                                                autonomic nervous system






Conture proposes an alpha-delta hypothesis. Children’s whose speech contains more stuttering contains alpha behaviours (is more Sensitive to Stress (STS) rather than Resistant to Stress (RTS). The model gives three subgroups of stuttering children:

1. Those apt to recover from stuttering with or without intervention (40-50%)

2. Apt to recover with intervention (40-50%)

3. Sudden traumatic onset who need psychosocial evaluation & counselling (5-10%)

Conture gives behavioural descriptions of Alpha, Beta Gamma & Delta stages and say they occur in order of occurrence.





Perkins (1992) feels that speech production is the result of countless neural decisions, its final assembly involving two major components: speech sounds and syllables. If these two are not readied synchronously then stuttering will result. Two causes for this state may be brain injury and heredity and are therefore hard to treat. "The third, and most likely cause, is a dominance conflict about being assertive - about being in control" This can then delay syllable processing. Some more selected quotes illuminate his views:

"A dominance conflict depends on expectations of assertiveness, of the ability to control a speaking situation, whether our status be dominant or subordinate"

"When we feel that our listener accords us less respect than we feel we deserve, yet do not feel free to protest, then a dominance conflict sets in"

"The effect of conflict is a triple whammy - it retards how fast we can integrate syllables and sounds, while at the same time speeding up how fast we actually must integrate them, and then tightens throat, mouth or chest"

"Without a dominance conflict there would be no need for the pay-offs of stuttering"

"Sadly, reprimands are better than no attention. Because stuttering is required to get a response, stuttering is what receives the pay-off."





Multifactorial models of stuttering development focus on the interaction between environmental and innate factors. While this is intuitively appealing Packman & Onslow (2000) express concern that environmental factors drive many early intervention programmes even though their role in onset and persistence has not yet been tested.  To clarify this role they present a model of role of environmental factors:

Causal - thought rather to interact with innate factors

Maintaining - does this mean that the causal factors are no longer active?

Mediating - (the communication context affects the stuttering) more evidence of this

Ameliorative - nothing is known about this in natural recovery. In treatment programmes the environment is targeted but has not been driven by theoretical principle but rather by empirical support for the therapy.






Looking at the development of stuttering within the family context has been in the forefront in recent years. The family’s anxiety level is taken as one of the strongest criteria on which to base the decision to intervene with a child, the notion of bi-directional communication is examined closely when searching for why moments of stuttering occur, family communication patterns are assessed as well as a child’s speech and therapy for the young child is firmly based within the family environment. Quarrington (1966) first suggested that the development, persistence and maintenance of stuttering is a bi-directional process involving both listener and stutterer. The child contributes to the interactive process as much as the parent.


Fluency disrupters are summarised by Botterill, Kelman and Rustin (1991)


·      rapid rate of parental speech

·      poor listening and turntaking

·      parental questions

·      adult response time latency

·      syntactic and semantic complexity of parents’ speech

·      directiveness

·      non-verbal behaviour


More recently, Yaruss and Conture (95) and Sims, Rees & Cook (2000), have found that rather than there being significant differences between the speaking rates of parents of stuttering children compared to non-stuttering children, findings concern the difference between parent and child speaking rates in conversation. Stuttering children and their parents show larger differences than non-stuttering children and parents.


Parent -child interaction work has its origins in the work of Johnson. While this lost popularity interest was sustained in the role of families, especially with the advent of parent - child- interaction studies in other areas of SLT. There was great concern that mothers (fathers added later!) were talking inappropriately to their stuttering children but while it may be the case that improvements can be made it seems unlikely that they are a major factor in causing the disorder.

Stewart & Turnbull (1995)  examined the literature on parent-child interaction and the following list is extracted from their book “Working with Dysfluent Children”


1. Parents of stammering children are no less tolerant of dysfluency than the parents of non-stammering children (Berlin 1960)


2. Parents of stammerers tend to have a higher percentage of negative statements in their conversations than parents of non-stammerers (Kasprisin - Burrelli et al 1972)


3. Parents and other adults are likely to talk more rapidly to stammering children than to non-stammering children (Meyers & Freeman 1985b)


4. Reductions of parental speech rate are significantly correlated with the extent of improvement in children’s stammering during treatment (Starkweather & Gottwald 1984)


5. Mothers of stammerers and mothers of non-stammerers interrupt their children during dysfluent speech (Meyers & Freeman 1985a)


6. Mothers of stammerers may be more overtly accepting but covertly rejecting than the mothers of non-stammerers (Kinstler 1961)


7. Stammerers’ parents are more rejecting or anxious than parents of non-stammerers (Flugel 1979)


8. There are few or no general differences between stammerers’ parents and parents of non-stammerers (Goodstein 1956; Goodstein & Dahlstrom 1956)


Embrechts & Ebben (200) report on a study showing no significant differences between mothers or children in terms of parent-child interaction, a finding which is tending to appear in more of the related studies, but they did find that the stuttering child’s temperament was significantly different to the extent that their mothers perceived them  to be more “difficult”.



HAYHOW (1995)

Hayhow (1995) considers a model of the development of stuttering which “attempts to take account of the child, the family and their interaction with each other”. Whatever the cause she considers the way that disfluency is construed by the parents and sometimes the child after it first occurs and that, from the point of view of therapy - if a family member can learn to view the issue through another’s eyes this will undoubtedly lead to greater understanding and often a reduction in tension. The model shows, for example, how a fleeting awareness in the child that talking can be difficult will make them try to talk better and therefore focus on words and situations. She also talks about how attempted solutions to the problem can in fact become an intrinsic part of the problem - easily exemplified through avoidance and increased tension. She uses ideas from Watzlawick (1974) on problem formation in relation to Brief Therapy.




In 1972 Fransella proposed that children might stop taking speech for granted if they are disfluent because they focus attention on it. This happens initially through parent - child interaction when disfluencies and not fluencies are pointed out. There are 1) brief emotional reactions 2) frustration 3) exasperation, annoyance and disgust and 4) fear and embarrassment.  Stuttering becomes "not a symptom but a way of life".


This change to looking at development from a multiplicity of angles rather than just one is seen as a healthy trend by our profession. Dean Williams (1985) in "prevention and intervention with Children" cites many authors who are now stressing the interaction between numerous factors - expressive and receptive language abilities , speed and timing of motor responses  and neuromotor, cognitive and emotional spurts in growth. Not all these children will have all these factors but Williams discusses how we can identify emotional and environmental factors. Smith 1992 also stresses the multifactorial origins

Onslow (1993) summarises the studies which indicate that stuttering is episodic and very variable.


Some general findings about the development of stuttering have been listed by Starkweather (1987) in "Fluency and Stuttering". (hard copy from the lecture).





Reading Guide


Adams M 1982 Fluency, non-fluency & stuttering in childrenJ F D 7

Andrews and Harris 1964The Syndrome of Stuttering

Baker K , Rustin L & Cook F Proceedings of the Fifth Oxford Dysfluency Conference July 99 Published 2000 (chapters available from Roberta)

Bernstein Ratner N 1994 Language and Stuttering In Topics in Language Disorders

Bloodstein 1970Stuttering and normal non fluency: a continuity hypothesis  BJDC 5 30 -39.

Bloodstein (1995) A handbook on stuttering Chapter 9

Conture E. 1982/1995 Stuttering

Dalton (Ed) 1983Approaches to the Treatment of Stuttering  Chapter 2.

Dalton & Hardcastle 1989Disorders of Fluency  Chapter 6.

Hayhow 1995 Stuttering and the family in Stuttering: from theory to Practice (Ed) Fawcus M

Guitar B (1998) Stuttering: an integrated approach to its nature and treatment Chapter 5

Myers and Wall 1981Issues to consider in the differential diagnosis of normal childhood non fluencies and stuttering  JFD 6 189 - 195

Myers & Wall 1995 Clinical Management of Childhood Stuttering

Onslow M 1993 The Behavioural Management of Stuttering

Perkins W 1992. Stuttering Prevented Section I.

Riley & Riley 1979A component Model for diagnosing and treating children who stutter  JFD 4 279-293

Rosenbek (1984) Stuttering secondary to nervous system damagein Curlee & Perkins Nature & treatment of stuttering New Directions College Hill Press

Rustin L (Ed) 1991 Parents families and the stuttering child Far Communications

Starkweather 1987 Fluency and Stuttering

Stewart & Turnbull 1995 Working with the dysfluent childWinslow Press

Van Riper C 1982 The Nature of Stuttering Prentice Hall

Watzlawick, Weakland & Fisch NY Norton  1974  Change: Principles of problem formation and problem resolution

Wingate (1988) Stuttering: a psycholinguistic analysis NY Springer Verlag

Yairi (1981) Disfluencies of normally speaking two year old children JSHR, 24 490-495

Yairi E & Ambrose N 1992b Onset of stuttering in pre-school children: selected factors JSHR 35 782-760

Yairi (2000) see Baker, Rustin & Cook above