Glossary of Terms for Childhood Apraxia of Speech

Childhood apraxia of speech (CAS) is the current preferred terminology to describe the disorder. Other terms still in “use” and from the relatively recent past include “developmental apraxia of speech” and “developmental verbal dyspraxia”. Use of the descriptor “developmental”, however, unfortunately provides a false implication to other professional groups and insurance reimbursers that the speech difficulties of affected children are akin to “delays” in development; are transient and can be simply outgrown without direct intervention.

The use of the prefix “A” (i.e.: absence) and “dys” (i.e.: partial) attached to the root word praxis may also provide confusion. In most instances, use of either of the terms apraxia or dyspraxia appear to be based on personal preference, one’s graduate educational institution, and/or one’s geographic location rather than a substantially, meaningful or practical difference. The term apraxia, however, is the choice used nearly exclusively to describe the adult form of the disorder. Praxis, in either case, refers to “skilled movement.”

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Additional definitions:

AAC (Augmentative/Alternative Communication) – Use of communication modalities in conjunction with oral speech such as sign language, picture boards, gestures, and voice output devices

Apraxia“A” means absence or without and “praxia” from the root word “praxis” means movement; Apraxia translate to without movement; is used interchangeably with Dyspraxia

Articulationthe act of using the Articulators to form words and sentences for spoken language

Articulation Disorder – Having one or a few specific sounds in error such as an “s” lisp or an “r” distortion

Articulators – The tongue, lips, jaw, teeth (more of a static one) and the palate

Comorbidities – The simultaneous presence of two conditions (e.g. CAS and autism)

Cues/Cueing – Acting as a prompt or reminder to facilitate verbal speech or another targeted goal are usually multi-sensory

Diadochokinesis – The ability to execute rapid repetitive movements of the articulators (usually tested with sequences such as “pataka”)

Diphthong – A sound made by gliding from one vowel to another in one syllable such as “oy”. In most English dialects, “oy” (boy), “ow” (cow), “”ie” (pie) and “ay” (hay) and “oe” (doe) are diphthongs

Dysarthria – a neurological disorder resulting in muscle weakness which causes speech sound distortions and often also reflected in drooling and problems with eating

Dysphasiadifficulty with skills for eating – chewing and swallowing

Dyspraxia“dys” means partial and “praxia” from the root word “praxis” means movement; Dyspraxia translates as partial movement; is used interchangeably with Apraxia

Dysfluency – An involuntary disruption in the flow of speech, as the result of attempts to figure out a speech motor plan, word retrieval difficulties, or possibly as a result of true stuttering

Early Interventionfree (usually) services provided in the home to children under school age (3 or 5 years depending on the state) including OT, PT, Speech, parent training

Expressive Language – the words we use and how we use them to share ideas and get what we want through vocabulary choice, word order, etc.

Fine Motor Skillssmaller motor movements involved in tasks such as coloring, writing, using a fork, stacking blocks, buttoning…

Global Apraxia – Having other motor planning struggles in addition to speech motor such as fine and gross motor planning difficulties; sometimes called motor apraxia or limb apraxia

Groping – Struggling to find where the mouth goes to produce a sound

Gross Motor Skillslarge motor movements involved in tasks such as walking, jumping, riding a bike, throwing/catching a ball, stair climbing…

Hypotonia – Decreased muscle tone (the amount of tension or resistance to stretch in a muscle) that can result in “floppiness”. Is not equivalent with weakness.

Intelligibilityusually judged as a percent of words/utterances that are understood by the listener. A typical 3 year old child’s speech is 75% intelligible or understood about 75% of the time.

International Phonetic Alphabet (IPA)  – symbols to represent each sound in a language

Languagethe use of grammar and vocabulary that makes up communication and the social use of words/sentences to communicate

Literacyall aspects of reading and writing

Motor Speecha general term referring to the process of planning, programing, and executing the movements needed for speech production

Motor Speech Disorder or Speech Motor Disorder – A cover term used to describe Motor Speech sound impairments such as Apraxia and Dysarthria

Multi-Sensory/Multi-Modality – Using a variety of nonverbal/verbal cues that use different senses (visual, auditory, tactile) to support speech such as gestures, touch cues, visual prompts, pictures, and sign language

Nasal soundsNasal sounds are where air is pushed out through the nose instead of the mouth. In English, there are 3 nasal sounds: “n”, “m”, “ng” (sing).  All other consonants and vowels are non-nasal sounds.

Occupational Therapyprovides treatment for difficulties with smaller or Fine motor skills and sensory processing disorders

Oral Apraxia – Difficulty executing non-speech oral movements (e.g. smiling, pursing lips, etc.)

Oral-Motor – Having to do with movements and placements of the oral structures such as the tongue, lips, palate and teeth. (with no speech)

Perceptionthe ability to detect or perceive stimuli through the senses – touch, hearing, vision, smell

Language Processing – Understanding speech and language at varying levels of complexity. Also called language comprehension or receptive language.

Perseverative – Continued or repeated act, activity, or verbalization insistently/redundantly

Phonemes – Meaning-based speech sounds in a language – consonants and vowels that can be used in isolation or combined into a syllable or word to carry meaning

Phonetic – How speech sounds are produced and their acoustic properties such as voiced or unvoiced; nasal or non-nasal

Phonological Disorder – Having problems with the “rule” system of speech sounds which underlies the learning of putting sounds together to form words in the language. (e.g. Leaving off the final sound in a word changes the meaning: “bow” is something a girl wears in her hair, and “boat” is something that floats on the water.  /s/ can be combined with certain other sounds at the beginning of a word such as “stop” “snake” and “school” but not with other sounds like /sd/ or /sj/)

Phonological AwarenessPre-literacy skills children usually learn between ages 3 and 5 years to prepare them for reading such as rhyming, sound identification, sound blending, sound-letter association

Physical Therapyprovides treatment for difficulties with large or Gross motor skills

Pragmatic skills – Social language skills including non-verbal communication (eye contact, facial expressions, body language) and how appropriate our interactions are in a given situation – such as carrying on a conversation appropriately

Elicited/Imitated productions – Non-spontaneous and produced upon request or following a model

Prognosis – A prediction of the likely outcome of a disorder or disease process

Prosody – Features of verbal production that are non-sound related such as pitch, volume, inflection, syllable/word stress, and speech rate – the intonation and rhythm of speech production.  Is usually affected by CAS.

Receptive Language – understanding words and language that we hear (spoken), read (written), or see (signed); also called language comprehension or language processing or auditory comprehension

Sequencing – The order in which sounds are combined into syllables, syllables into words and words into sentences

Sensory Processing Disorder (SPD) – when the brain had difficulty receiving and processing information that comes from any of the senses

Speech – the use of sounds to form words/sentences for spoken language.  Also referred to as Articulation

Speech Delay – Learning to talk or use words later than other typically developing children of the same age

Speech Language Pathologist (SLP)a person with a Master’s degree trained to treat all types of speech, language, communication and swallowing disorders (in the US and Canada).

Spontaneous Speechspeech that is produced without a model. In an evaluation, a sample of the child’s spontaneous speech is usually collected.

Temporal – Having to do with time and timing of the articulators and voice to produce speech sounds correctly

Vocalizations any speech or non-speech sounds produced with the mouth; includes grunting, cooing/babbling, crying, laughing

Voiced Sounds – Sounds produced with vibration of the vocal cords. (”b”, “d”, “g”, “z”, “j”)

Voiceless Sounds – Sounds produced without vocal cord vibration (“p”, “t”, “k”, “s”, “ch”)

Volitional productions– Made through conscious choice, decision, and intention.  Can be in response to a stimuli such as a question or a model or spontaneously – on their own.



These two terms are generally synonymous. Developmental verbal dyspraxia is often shortened to “DVD” and childhood apraxia of speech to “CAS”. The “a” in “apraxia” stands for absence and “dys” in dyspraxia stands for partial. Thus, apraxia is absence of speech and dyspraxia is used by some to indicate some speech ability. “Praxis” indicates difficulty executing skilled movements.  Thus, both terms focus on the core challenges of the child who has difficulty with speech  motor planning and programming.   However, more recently Childhood Apraxia of Speech is the preferred term for describing apraxia of speech in children.  It is the preferred term because it encompasses all children who show symptoms of the disorder, including those who acquire it in childhood through illness, injury or accident.  Additionally, nonspeech professionals often interpret the word “developmental” as meaning the child is capable of outgrowing it.  That is not the case for children who have speech difficulty due to apraxia.   They do  not outgrow the problem without specific, targeted speech therapy help.


Oral apraxia indicates that the child has difficulty with volitional control of nonspeech movement. For instance, perhaps the child will have difficulty sticking out and wagging their tongue when requested to do so. Or the child may have difficulty sequencing movements for the command, “Show me how you kiss, now smile, now blow”. Verbal apraxia indicates that the child has difficulty with volitional movement for the production of speech. This can be at the level of sounds, syllables, words, or even phrases (connected speech). The motor struggle is most typically seen with sound sequencing.

Often oral apraxia accompanies verbal apraxia, but that is not always the case. Speech and language pathologists have mentioned that it is very rare and fairly unheard of for a child to have oral apraxia without verbal apraxia/dyspraxia.


In the course of discussing apraxia, as we have above, you will note the use of the word “volitional”. The meaning of this word in relationship to apraxia/dyspraxia of speech means that the child is experiencing the difficulty in nonspeech and speech movement when they are very consciously aware of trying to make movements or they are attempting movements when requested by others. Those same movements, sounds, etc. may be heard while the child is busy playing or he/she just seems to blurt out when no one is really paying attention or trying too hard. As an example, the child may be playing happily and parents may hear sounds being made – almost without thought – “ma, ma, ba, ma,da”. However, when the parents attempt to get the child to use those sounds – “Say Mama!”- the child is unable to do so. In many cases one can see the struggle on the child’s face. They may grope with their lips or silently posture their lips as if searching for the position they need. One minute they could do it (when not thinking about it or attempting the task) and the next minute it is an intense struggle (they are now aware of the request and are trying to will their mouths to make those movements – volitional control).


What is meant by “pure” apraxia of speech is that no other speech, language, cognitive, or sensory issues coexist with the deficit of impaired sequencing for volitional speech (apraxia). The professional literature tells us that “pure” apraxia of speech in children is rare, that most often apraxia is associated with other speech, language, cognitive, and/or sensory issues. Paula Square states that,

“In its purest form, acquired apraxia of speech does not coexist with language impairments, auditory processing deficits, or cognitive deficits. Nonetheless, ‘pure’ apraxia of speech rarely occurs. Coexisting deficits for expressive language, psychoacoustic processing, and motor execution are likely to occur in both acquired apraxia of speech and DAS (developmental apraxia of speech) because of the proximity of the neural structures underlying each of these processes to those that generate programs for praxis. A review of the literature suggests that co-occurence of language impairment with both acquired apraxia of speech and DAS is frequent…”

Associated issues might not be apparent in a young child. This is especially true in children who are young preschoolers. For instance, these children may not have any apparent problem with receptive language according to traditional and typical assessment. However, the child may begin to experience difficulty when entering kindergarten, when the language processing demands of the setting are heightened. It would not be unusual to then identify higher level language processing problems. Parents and professionals will do well to be vigilant about the child’s total development to insure that, should an associated area of difficulty arise, help for the child will be readily available.

Your two-year-old says no words, makes some sounds, yet he understands everything you say. Your five-year-old speaks in what appear to be sentences, but all you hear are vowel sounds. Your seven-year-old lisps, and says “wabbit” instead of “rabbit”. And your three-year-old talks non-stop, but no one can understand a word that he says. So what do you do? If you bring your child to a speech-language pathologist (SLP), the first two children would probably be diagnosed as having oral-motor planning deficits, or Childhood Apraxia of Speech (CAS). The third child has an Articulation disorder, and the fourth child has a Phonology disorder. Now that you know that, what does it all mean?


Childhood Apraxia of Speech is a deficit in the ability to plan the motor movements for speech and is considered a speech motor planning disorder. Children with CAS have difficulties transmitting the speech message from their brain to their mouths. Children with significant weakness of the lips, tongue, and jaw may be diagnosed by a neurologist as having Dysarthria. Many children with cerebral palsy and multiple sclerosis have Dysarthria. CAS is usually of unknown origin. Whether or not we know the cause, SLPs can treat the disorder.

Motor speech disorders are diagnosed by the SLP directly observing the child and completing an examination of both the childs speech and oral mechanism. The oral mechanism exam involves the SLP asking the child to do a variety of tasks (such as pursing lips, blowing, licking lips, elevating tongue, etc.), looks inside the child’s mouth, observes the child eating, and listens to the child talk. The therapist will also listen for the child’s ability to produce rapid oral movements. A diagnosis of CAS involves consonant and vowel distortions, distorted sound substitutions, error inconsistency on repeated production of a word, and prosodic errors (prosody refers to pitch, rate, and rhythmic features of speech). Some other behaviors which may be seen in CAS include groping, perseverative errors, and increasing errors as the length of utterance increases. The SLP will determine how “intelligible” the child is (how much of what the child says can other people understand?), and may complete a formal test (like the Kaufman Speech Praxis Test). Like a detective, a good diagnostician looks at many variables before making a diagnosis.

For children who have CAS, therapy should address the movement patterns in syllables, progressing from the simple (one-syllable words with similar sounds at the beginning and end, like “pop” “mom” and “cake”) to the complex (multi-syllabic words with many different sounds). There may also be a need to teach more functional responses (e.g. yes, no, I want, I dont want, I need, etc.). In more severe cases of CAS, a child may require an alternative/augmentative form of communication, such as sign language, a communication board, or an AAC (Augmentative/Alternative Communication) device. These are not intended to replace oral speech, but in fact, to facilitate it and to provide the child with a means of communicating with others. Therapy also needs to address prosody. Frequent drill and repetition is required for therapy to be successful. Intense, individual therapy is ideal for CAS. Group therapy is not recommended for CAS, and children with moderate to more severe deficits will require therapy for a number of years.


When a child has a simple lisp (producing [th] instead of [s], like “thing” instead of “sing” or “yeth” instead of “yes”), substitutes [w] for [l] or [r], or other similar errors, they are demonstrating an articulation disorder. Articulation refers to the manner in which a child produces a sound and the placement of the tongue, lips, and teeth. Common articulation errors are those listed above, in addition to [f] for [th] (“fum” for “thumb”), [l] for [y] (“lelo” for “yellow”). Traditional thinking has been that some articulation errors are developmental in nature (e.g. s, l, r) and that children may not be ready to address them in therapy until a specific age (typically 7 or 8). However, however, current research has disproved the idea of developmental norms for articulation, and in fact, current best practice involves starting treatment with the more difficult sounds. In addition, the earlier therapy begins, the more successful it will be. Articulation errors may not significantly reduce the child’s ability to be understood.

Articulation therapy consists of drill exercises and various cues to help the child correct their sound productions. These cues may be verbal (e.g. tell the child where to place his tongue) or visual (having the child look at the therapist’s mouth or in a mirror) or tactile (i.e. touch; e.g. having the child slide their finger down their arm when making the [s] sound). Frequent practice is essential for articulation therapy to be successful.


Phonology is the sound system of language. The phonology of language tells us how sounds fit together in words. Children who have phonology disorders have not learned the rules for how sounds fit together to make words, and use certain processes to simplify words. Phonology disorders are related to language and reading and are now seen as a language-based disorder. Children with phonology disorders are frequently unintelligible; often, their parents are the only ones who can understand them, and even they have difficulties. Children with these disorders are at a very high risk for later reading and learning disabilities, and should be treated with intensive speech therapy as soon as they are diagnosed, as early as age 3.

A phonology disorder is most commonly diagnosed using the Assessment of Phonological Processes by Barbara Hodson. This test analyzes (by hand, or through a computer program) the patterns that a child is producing as they say 50 words. A phonological analysis can also be completed informally. There are other tests for phonology available, but the Hodson is the most widely used.

There are many different phonological processes which SLP’s see and treat. One of the most common is called “cluster reduction”. Children who use this process will take a sound blend (like [bl] [sp] or [tr]) and omit one of the sounds: “blue” becomes “boo”, “spoon” becomes “poon”, and “tree” becomes “ti”. Another common process is called “velar fronting”. Children who use this process substitute sounds produced in the front of the mouth (t, d, n) for sounds produced in the back of the throat (k, g). In this instance, “duck” becomes “dut”, “car” becomes “tar”, “go” becomes “do” and “can” becomes “tan”.

Therapy for phonological processes involves making the child more aware of the correct sound patterns (rules) and drilling the new patterns. Awareness is frequently achieved through what is referred to as “auditory bombardment”; using an amplifier and headphones, the therapist will repeatedly say words using the correct patterns. One popular therapy technique for remediating phonology disorders is called “cycling”, developed by Barbara Hodson. In this approach, auditory bombardment is used, and children work on a specific process for a period of time, then move onto the next process, and so on. Once through all of the processes that need remediating, the cycles are repeated again and again. Another very effective technique is called “minimal pairs”. In this technique, the therapist will present a pair of words to the child that addresses the incorrect sound pattern and enables the child to first discriminate, and later produce, the differences between sound patterns; e.g. if the child is omitting sounds in blends, a pair might be “Kate”/”skate” or “cool”/”school”. If velar fronting is the problem, then a pair of words might be “tar”/”car” or “tan”/”can”. A good therapist will use a variety of techniques in order to maximize therapy time.

The most important thing to remember about speech production disorders is that therapy can, in most cases, make a huge difference. The earlier and more intensive the intervention, the more successful the therapy. Group therapy can be effective for articulation disorders and some phonology disorders, but children with CAS really need the intensive, individual therapy.


Published 2003 | By Nancy Lucker-Lazerson, M.A., CCC-SLP
(Updated by the author October 2003)