What are the signs of childhood apraxia of speech?

What is childhood apraxia of speech, and is it the same as DVD?

Yes, they're the same condition under two names. Childhood apraxia of speech (CAS) is a rare motor speech disorder that makes speech harder to understand. In the UK it was called developmental verbal dyspraxia (DVD) until 2024, when the RCSLT switched to CAS in all contexts, so you'll still meet both names.¹

In plain terms, a child with CAS knows what they want to say, but planning and sequencing the mouth movements for speech doesn't work as precisely or consistently as it should. ASHA's definition says this happens without weakness in the muscles themselves, such as abnormal reflexes or tone.² The RCSLT estimates CAS at about 0.1%, or one child in a thousand.¹

What are the signs?

Three features have gained some consensus among researchers, and therapists look for them together.² ASHA is clear that they aren't proposed as a complete test, and that the signs change with a child's age and how severe the difficulty is.² Its technical report concludes there's no single validated list of features that separates CAS from other speech sound disorders.³

• Inconsistent errors on consonants and vowels when the same syllable or word is said more than once
• Lengthened, disrupted movement between sounds and syllables, which can sound slow, distorted or staccato, and you may see awkward movements¹
• Unusual stress or rhythm, for example giving every syllable the same stress¹

Therapists also notice groping or silent searching movements of the mouth, and vowels that sound as if they're halfway between two others.¹ Some of these signs also appear in other conditions, such as dysarthria (a speech difficulty caused by weakness or poor control of the speech muscles), which is why careful assessment matters.¹ Seeing one or two of these in your child doesn't mean they have CAS.

Why is it hard to diagnose in very young children?

Because CAS is recognised from how a child speaks, and very young children don't say much yet. The RCSLT says it can't be identified with confidence until a child has some spoken output and the therapist can find evidence of the typical speech and rhythm features. If a child has little or no functional speech and can't attempt to copy, a definitive assessment may not be possible yet.¹ ASHA adds that diagnosis is particularly difficult under 3, that the youngest age at which CAS can be diagnosed hasn't been established, and that a therapist may use a provisional wording such as "signs are consistent with CAS".²

So you may hear a cautious answer, which usually reflects how hard the diagnosis is. There's a second reason for care. The RCSLT warns therapists about over-diagnosis and cites a study of 47 children identified with CAS by community therapists. On a second look, 28 had CAS and four had CAS alongside other difficulties. Fifteen didn't have CAS but had something else, such as a cleft hidden under the lining of the roof of the mouth, a phonological disorder or dysarthria, which was going untreated.¹

How is it different from other speech sound difficulties?

Most children who are hard to understand don't have CAS. Of the children referred to speech and language therapy with a speech sound disorder, between 80% and 90% have a phonological disorder or delay, and between 0.2% and 2.4% have CAS.¹

A phonological difficulty is about patterns in how a child uses sounds. A child might say k and g fine on their own but say "teep" for "keep".⁴ CAS is about planning the movements, so errors are often inconsistent and speech can sound effortful. The easiest one to confuse with it is inconsistent phonological disorder, where a child also says the same word differently each time, and the RCSLT says the three features above help to tell them apart.¹ Expressive language difficulty, where a child has trouble putting words together, can look similar in very young children, and some children have both.¹

Who can diagnose it?

A speech and language therapist with the right training can diagnose it. The RCSLT says CAS and dysarthria are diagnosed and treated by speech and language therapists, and ASHA says the diagnosis belongs with a clinician who has specialist knowledge of motor learning and of telling motor speech disorders apart.⁴² The assessment includes the child's history, a hearing check, an assessment of language, and a standard test of articulation and phonology.¹

I assess for the signs and tell you what I see. Some children need a medical or other team involved as well, and I'll say so if yours does.

What does therapy involve, and how strong is the evidence?

Therapy involves a lot of focused practice of speech movements, and the evidence for it is limited. The RCSLT says children with CAS can improve when they get the right therapy in the right amount, and lists five approaches with the strongest evidence, including ReST (Rapid Syllable Transition Treatment) and the Nuffield Dyspraxia Programme.¹

The 2018 Cochrane review found only one randomised trial: 26 children aged 4 to 12, given ReST or the Nuffield programme in one-hour sessions four days a week for three weeks. Both improved word accuracy at one month, but with a single trial the reviewers called the evidence limited. They couldn't say that either was better than the other, or than no treatment.⁵ The trial's authors found large effects for both and better held gains at four months with ReST.⁶

More intensive therapy tends to work better. The RCSLT says four sessions a week in blocks of 12 to 16 sessions, followed by a four to six week break, is the most effective schedule, though as few as two sessions a week can also work.¹ In my experience that's a lot for a family to fit in, so we'd talk through what's realistic. In my sessions, practice stays short and playful and begins with words your child wants to say. Mouth exercises that don't involve speech, like blowing or tongue wiggling, have no evidence of benefit for CAS.¹ Signs, pictures or a communication app can sit alongside therapy, and my page on AAC explains how.

I've done the introductory training, Introduction to PROMPT: Technique, so I'm trained in it, not certified. The research is still limited. One randomised trial of 49 children with severe speech motor delay (not specifically CAS) found improvements in speech motor control, articulation and word-level clarity after ten weeks compared with a waiting list, and only weak improvements for sentences and everyday communication.⁷ PROMPT isn't one of the five approaches the RCSLT lists with the strongest evidence for CAS.¹

The RCSLT says outcomes are likely to be good with the recommended approaches, but they vary. Some children end up with no obvious difficulty, some with leftover speech or rhythm differences, and a small number need AAC or other support long term.¹ I can't tell you where your child will land.

When should I ask for help?

If your child is hard to understand beyond the family, says the same word differently each time, or seems to be searching for the movement with their mouth, ask. Your health visitor, your GP or the SENCO (special educational needs coordinator) at your child's nursery or school can all take your concern further at no cost. Some NHS speech and language therapy services take referrals from parents and some only from health visitors or schools.⁴

A few things need prompt medical advice. If your child has lost words or speech they had, see your GP promptly. If they have difficulty swallowing, or cough or choke while eating or drinking, ask for an urgent GP appointment or call NHS 111, and mention any weight loss.⁸

What happens if I get in touch?

Start with the free 15-minute call. If an assessment makes sense, it's mostly play: I listen to your child's sounds and watch how their mouth, jaw and lips move, and it costs £270. You don't need a GP referral, and seeing me doesn't take your child off an NHS waiting list. My speech sounds and apraxia page has more, and the fees page lists every cost.