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Speech and language therapy

Speech and language therapy

The profession

Speech and language therapy involves referral, diagnosis, assessment and treatment for a range of conditions. These include hearing loss, learning to read and learning to write, dysphagia, speech and language impairment (expressive and receptive impairment), metalinguistics and metalinguistic awareness, specific language impairment, articulation and speech sound disorders, semantic pragmatic disorder, dysfluency (or stammering or stuttering), dysphonia, childhood apraxia of speech and verbal dyspraxia, and more.

Speech and Language Therapy has grown from the work of William Holder in the 1660s, John Thelwall in the early 1800s, and Alexander Melville Bell in the later 1800s. Their writings go beyond clinical observation and the discussion of therapy to foreshadow current generative linguistics.

In modern times, until the 1970’s, the term ‘speech therapist’ reflected a general focus on speech. From the 1970s, the focus broadened to include language and a variety of disorders, including Down’s syndrome and Autistic Spectrum Disorders. Then in the early 1990s, the focus broadened again to include dysphagia or disorders of eating and drinking.

Speech and Language Therapy is represented by the Royal College of Speech and Language Therapists on

Speech and Language Therapists have to register with the Health and Care Professions Council on

My professional status

I qualified as a speech and language therapist in 1979, going on to work in the NHS. I treated a broad range of issues. I then went on to do a PhD at the University of Durham. I now find that not being registered with the Health and Care Professions Council, or HCPC, I cannot call myself a speech and language therapist, and do not, therefore, do so. I am now in the process of registering with the HCPC. In the meantime, I work as a clinical linguist, specialising in those issues relating to the learnability space, in other words, those issues which arise because the process of learning to talk has somehow stopped or failed. I do not, therefore, treat swallowing disorders because I have no training or experienc in that area. I also write and carry out research.


The terminology is confusing at least partly because of the different beliefs and orientations of linguists, speech and language therapists, language teachers, and philosophers, both individually and as members of professional groupings, trained in different traditions. So the same term can be used for different conditions. And a given condition can be characterised by different terms. This is particularly problematic when diagnoses are entered into databases which don’t allow fudges or fuzziness. See also Modesty and caution, Framework and Ax, ex, ics and ologies.


Literally, Aphasia means no speech. But the term is generally used to mean a disorder of speech and language, typically as a result of a stroke or a disorder of the brain, but also sometimes in relation to the speech or language of a child.

Articulation Disorder

In the name of focusing on what seem to be points of particular difficulty, the term refers to the errors in the formation of speech sounds.

Asperger’s Syndrome

Sometimes taken to be a specific and distinct disorder and sometimes to represent an intermediate degree of affect on the ASD (Autism Spectrum Disorder) spectrum.


Ataxia is an umbrella term referring to a group of neurological disorders involving poor muscle control, clumsy voluntary movements, poor co-ordination of the hands, arms,.legs and feet, balance, swallowing, eye movements and speech. It is a clinical finding, not a disease.


Athetosis refers to a condition in which abnormal muscle contraction causes involuntary writhing movements, sometimes slow, sometimes violent, sometimes continuous, sometimes at seemingly random moments. It prevents maintenance of a stable posture. It affects some people with cerebral palsy/ impairing speech and use of the hands.

Attention Deficit and Hyperactivity Disorder ADHD

Children with ADHD tend to have difficulty paying attention and controlling their impulses. The diagnosis is sometimes welcomed by adults about themselvesnin the name of neuro-diversity,

Autism and Autistic Spectrum Disorder or ASD

A lifelong disorder commonly taken to be represented by three main deficits, in relation to communication, relationships, and flexibility of thought, which can be seen as either a distinct disorder or as representing the greatest degree of affect on the ASD (Autism Spectrum Disorder) spectrum. But there is an open question about the central core of the disorder,

Central Auditory Processing Disorder or CAPD or Auditory Processing Disorder or APD

Both terms refer to a difficulty with the PROCESSING of sound as opposed to REGISTERING it in the brain. The two most salient aspects of (C)APD relate to remembering sequences of letters, numbers, names, and discriminating particular sounds against a background of other sounds. It is quite different from deafness.

Cerebral Palsy

A group of lifelong conditions affecting movement and co-ordination, commonly in the form of athetosis, ataxia, or general weakness It is caused by abnormal development of part of the brain or by damage to parts of the brain often at birth. It is the most common motor disability affecting children.

Childhood Apraxia of Speech CAS and / or Verbal Dyspraxia

Some speech issues are known as Childhood Apraxia of Speech or Verbal Dyspraxia. Often as a proxy for severe phonetic and / or phonological problems with speech. (See Speech Impairment).


Author of over a hundred books and many more articles, the world’s most widely cited living author, honoured by twenty eight honorary doctorates. Part of Chomsky’s originality was to recognise how remarkable it is that speech and language are commonly mastered over about ten years without help or instruction, other than about what not to say. Much of his argument has always been driven by conceptual necessity or considerations of economy, simplicity and parsimony.

Cleft lip and cleft palate

By normal development, the palate and upper lips are initially separate, only fusing together in the course of development in the womb. This fusing sometimes fails to happen.

Clinical linguist and Clinical linguistics

Clinical linguistics is a way of looking at the situation of a child or adults said to have a ‘communication problem’ or a ‘difficulty saying some words’ or any of a number of issues that arise with respect to the ‘learnability space‘. The area is thus narrower than that covered by speech and language therapy in the broad sense. But it is correspondingly more focused.

Cochlear implants

A cochlear implant requires the surgical removal of the cochleus which is then replaced by an artificial device connecting a small microphone above the ear and the auditory nerve. The resolution of a cochlear implant is much less than that of the natural cochleus. In the Deaf community, cochlear implants are viewed negatively by some members.

Deafness and deafness

From the perspective of those with profound hearing loss, who think of themselves as ‘completely deaf’, there is a cultural issue between those who have had the good fortune to have experienced native-user signing from infancy, gone to a school where the first language was signed, commonly think of the condition as just a difference, not a disability, and call themselves Deaf, and those who chose not to emphasise any separateness, and are characterised by the Deaf as deaf. In my personal experience, the issues here were never more powerfully expressed than by a Deaf female lead playing a real life Deaf woman in Mark Medoff’s stage play Children of a lesser God. See also ‘Hearing loss and hearing impairment’.

Developmental Dysarthria

See ‘Dysarthria’.

Developmental Language Disorder

Without seeking to narrow down the reference, Developmental Language Disorder is an umbrella term covering difficulties joining words together by syntax or assembling them from roots and endings by morphology.

Developmental Verbal Dyspraxia

The former term for what is now mostly called Childhood Apraxia of speech.


Giving a name to a problem – a much more complex question than sometimes realised A broken bone, a torn muscle, a perforated appendix, are painful, and in the case of the last, potentially fatal. Although, in the framework here, the faculty of language is a property of the genome, and thus biological, the possible vicissitudes are enormously complex.


See ‘Stammering’.

Down’s Syndrome or Down Syndrome

By a missing chromosome, with global effects, but particularly severely on speech and language.


A difficulty with speech caused by a weakness in the muscles of the face, lips, tongue, vocal cords, or a lack of coordination between them, often with the effect of slowing or slurring, even incomprehensibility, similar to that of too much alcohol, either by brain damage or as an aspect of developmental incompetence.


See ‘Stammering’.


Once used to cover a broad range of disorders, but less so now, at least in the English speaking world, possibly because of the emergence of Psycholinguistics, as an academic discipline.


A commonly-enduring difficulty with reading and writing often co-morbid with one or more linguistic issues, particularly metalinguistic issues. See Being dyslexic.


Because humans learn to focus on one another’s faces, any departure from the normal proportions and symmetry of the face is noticed.


A disorder of eating or drinking, either as a result of neurological damage or developmental failure. Although speech uses much of the same musculature as eating and drinking, the tempo for speech is roughly a hundred times faster than for eating and drinking. Speech requires the integration of this musculature into the very complex procedures of language. And some aspects of the musculature are only required for one functionality or the other. The larynx is only relevant to eating and drinking to the extent that that it has to be tightly closed for speech. And side to side movements of the tongue and jaw are relevant only to chewing and clearing food debris from the mouth, other than in the possible case of a very small number of languages. What are known as lateral phonemes in English and other Indo-European languages involve lowering both sides of the tongue at the same time, thus allowing two airstreams inside the mouth. There is no side-to-side movement in any Indo-European language.

English writing

Using an almost unchanged alphabet, originally designed for Latin, with a very different Sounds,  and unsurprisingly hard to learn.

Expressive Language Delay and Expressive Language Disorder

Assuming that it is possible to disentangle what children say from what they know, seeking to capture the common observation that many children seem unable to form sentences normally, but able to respond by gestures and actions to questions and instructions. See Syntax and Master class with Catherine Renfrew.

Grapheme, graphemes, and the meaning of graphemes

A letter is an abstract representation of a speech sound. A grapheme is a way of representing this relation, as capital letters for the first sounds in the first words of sentences and for the first sounds in most names and I, and otherwise as lower case letters. The abstractness may be difficult for some children.

Hearing loss and hearing impairment

In broad clinical terms, there are two sorts of hearing loss. One sort of deafness, sometimes known as ‘peripheral’, relates to the ear drum and the tiny bones behind it, known as the ‘ossicles’, which do the extraordinary engineering job of both damping down the loudest sounds and amplifying the weakest. The ossicles are spring-loaded by tiny muscles which react to the loudness of the acoustic environment, and thus take time to react. The explosions of military weapons and fireworks are too violent and sudden for the ossicles to react. The everyday events of nature are not like this. The hearing of mammals has not evolved to deal with explosions. Not liking the sounds of explosions and running away from fireworks are natural responses for cats and dogs. The small and elaborate mechanism of peripheral hearing is impeded by any fluid around the ossicles. The other sort of hearing loss, known as ‘sensori-neural’, relates to the inner ear, an even more elaborate structure, known as the cochleus (Latin for cockle shell), with over 20,000 hair cells, each tuned to respond to a particular frequency of sound. Defects in both respects are matters of degree, and measured on logarithmic scales for both ears. These scales are by ‘Decibels’.  So a loss of 60 decibels means that only a millionth part of the acoustic energy is being registered. A loss of 90 decibels reduces this to a billionth. There is no such thing as ‘100 percent’ or ‘perfect’ hearing’. As with any mechanical system, there is always some loss. This is just a matter of degree. Even with the peripheral system completely destroyed, as by a gun fired next to the ear, some hearing remains. The peripheral system can be permanently damaged by long term fluid in the ear – by repeated infections. More profound degrees of deafness are by some defect in the cochlear system. Because the whole system is essentially a frequency filter, it is susceptible to damage over any particular range of frequencies. The difference between S from SH is carried mainly on high frequencies. N and M are distinguished mainly on low frequencies. Bean can can be mistaken for beam, or me for knee. Low frequency loss can make drum beats inaudible. See also ‘Deafness and deafness’.


Speech that is excessively nasal – with too much of the air stream through the nose. See ‘Resonance Disorder’.


Speech without sufficient nasality – either by the effect of a blocked nose or by the velopharyngeal sphincter not working correctly. See ‘Resonance Disorder’.


The effect of the vocal cords not vibrating together in the way that we hear as voice, with an effect often called ‘scratchy’ or ‘rasping’, typically by the effect of shouting or just talking too loud, too long.

Laryngeal Nodule and Laryngeal Polyps

The likely effect on the vocal folds of hoarseness if the condition is left untreated. A nodule is like a callous, and a polyp is like a blister.


Without adding to the many definitions, but only to say that here – and commonly in the world of Speech and Language Therapy – referring to ‘syntax’ or the joining of words together or ‘morphology’ or the forming of words (most commonly in English) by adding an -ING, -ED, or -S on the right.

Learning to read and learning to write

Writing attempts to represent what native speakers take to be the way they speak. Unsurprisingly, difficulties learning to read and write often follow difficulties learning to speak and talk – by a common co-morbidity.


A lisp is the most commonly used term for a difficulty pronouncing S and Z. The term is disfavoured by some speech and language professionals.

Metalinguistics and metalinguistic awareness

A common commonality between difficulties with reading and writing and with speech and language – in relation to the awareness of speech and language as such, that words can be said correctly or otherwise.

Mutism, Elective Mutism or Selective Mutism

A rare condition when speech is withheld, previously called ‘Elective mutism’, emphasising that the lack of speech was by choice. ’Selective Mutism’ emphasises that the mutism may be only in one situation, such as school, or with one parent, or only in one language in bilingual families.

Phonetic Disorder and / or Phonological Disorder

Linguistic ways of describing difficulties with ‘phonemes’ or speech sounds. The term ‘Phonetic disorder’ would most likely apply to a difficulty articulating one or more phonemes, such as S. The term ‘phonological disorder’ refers to a difficulty in relation to the whole system of phonemes, getting them into the right order, not combining them in ways not allowed in the target language, English for most readers here. For example, finger pronounced as TINNA, with the N sound doubled, is just not English. Phonological disorders often seem to involve the stress pattern in words, sometimes known as the ‘prosody’.

Phonological process / Phonological processes

Often taken to the signature of speech sound disorders, including saying key as TEA.

Receptive Language Delay and / or Receptive Language Disorder

Receptive Language Disorders refer to a difficulty supposedly with the understanding of language, often thought to be a more global deficiency than a difficulty with Expressive or Productive speech. But whereas a difficulty with the expressive use of speech is seemingly measurable by plotting what the child says in controlled, but often rather unnatural, situations, a difficulty understanding speech is much more difficult to assess and measure with sensitivity and accuracy. See Syntax and Master class with Catherine Renfrew.


Judgements are made, mostly by professionals, against a background of training, knowledge and experience, that some sort of intervention is necessary and appropriate. It is well known that neurological impairments of almost all sorts are commoner in boys than girls. It is also commonly believed that girls talk better than boys, that girls are more interested in conversation and boys more interested in competitive games. There may be a grain of truth in this belief. But the belief interacts with the clear evidence of differential neurological impairment. This has a significant bearing on referrals with some clinics having two times as many boys as girls and others having four times as many. Sometimes children themselves realise that they need help.

Resonance Disorder

The effect of the nasal resonator being impeded by the valve between the resonators, the mouth and the nasal cavity, known as the ‘velo-pharyngeal sphincter’, not opening correctly. See ‘hyponasality’ and ‘hypersnasality’.

Semantic Pragmatic Disorder

The term efers to a difficulty using language appropriately and understanding figurative and metaphorical language. The term is commonly used to characterise the point of least affect on the ASD (Autism Spectrum Disorder) spectrum.

Social Pragmatic (Communication) Disorder SCD

The term seems to be mainly used in North America referring to a condition which is at least very similar to Semantic Pragmatic Disorder.

Specific Language Impairment SLI

Specific Language Impairment seeks to capture the idea that speech and language disorders can be conceived as independent of other developmental issues. But there are many co-morbidities. So the term, SLI, has been largely abandoned.


In the world of Speech and Language Therapy and here, commonly used to characterise what linguists call Phonetics or Phonology – with interminable arguments between linguists about where one stops and the other begins.

Speech Impairment, Speech Disorder, Speech problems, Speech Sound Disorder

Referring variably to Phonetic or Phonological difficulties across a range of speech sounds. But speech is more than just assembling speech sounds to form words. First the sounds and syllables have to be formed. Then the syllables have to be assembled into structures known as feet. The system has to be learnt.

Speech Language and Communication Needs

A cover term referring to a range of issues covered by clinical linguistics, as well as fluency and voice disorders, and issues with reading and writing

Specific Language Impairment

The term is now going out of use because co-morbidities are so common amongst those children for whom the normal process of speech and language acquisition does not work out or seems to fail completely.


One stage is obvious, when children are using just single words or names, normalliy but very approximately from around one, and another stage when children start combining words, normally, but again very approximately, some time before two. Even more vaguely there is a stage when most people can understand most of what a child says most of the time, normally around three and a half, and the point at which speech and language are both completely adult-like at least for the overwhelming majority, at least by ten. But the age-values here are very difficult to determine accurately. even for a researcher’s own children who can be observed much more assiduously than any child in a research environment. See Carol Chomsky (1969), Roger Brown (1973), Neil Smith (1973) for three very different approaches. The hypothesis here represents a more modern take on the issue, but it is only a hypothesis.

Stammering, Stuttering, Dysfluency, Disfluency,

By most understandings, the four terms all refer to the same thing. But there is an unresolved debate as to whether the disorder is one of attitude, self image, habit, family structure, and so on, or one by an internal neuro linguistic deficit.


The recognition by parents, professionals, and possibly a child or young person (less and less possibly, more like certainly as the child grows in age, judgement and self awareness) that some sort of intervention is necessary and appropriate. This can be anything from a single encounter to a relationship lasting over a number of years or the whole of childhood.

Voice Disorder, Dysphonia

When the vocal cords or vocal folds are brought together they vibrate with a kind of waving motion along their length by what is known as the ‘Bernouilli effect’, alternately closing completely and separating with a small gap between them. In slow motion it looks like the fluttering of a flag or the flapping of a sail. The acoustic effect is a buzzing sound which is modulated in the vocal tract to form the sounds of speech,

Williams Syndrome

Williams Syndrome is the result of.a defect on Chromosome 7, with effects on the shape of the face, heart, height, cognition and language, People with Williams Syndrome tend to be uncommonly sociable.


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