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Vowels Errors in Childhood Apraxia of Speech

Oct 13, 2023

Vowel errors are common in children with apraxia of speech.


Vowel errors significantly affect intelligibility.  It is one of the discriminative characteristics of childhood apraxia of speech.  Apraxia therapy must address vowel errors.


Please note: I will be using the international phonetic alphabet symbols in the blog post which can be found at the bottom of this post


Vowel errors include distortions, substitutions and reduction of a diphthong. A diphthong is a vowel that includes two vowels. i.e. /ai/ in the word "eye" or /ou/ in the words "down".  This requires the child to produce two vowels on two different planes of movement.  The child needs to produce vertical jaw movement and then retract or round the lips on the horizontal plane of movement.  The child usually reduces the diphthong and only produces the first vowel. 


Why do children with apraxia have so much difficulty with vowel sounds?

  • Vowels are not as visible as consonant sounds and they need vocal fold vibration. 

  • The changes in the motoric movement for pure vowels are very subtle. Say the word "bIg" (big) and "big" (beeg).  There is a very slight change in the tension of the tongue for these vowels. 

  • Many children distort neutral vowels such as the sounds /ʊ/ in book, /ɛ/ in bed /ʌ/ in bus and /ɪ/ in big

  • Poor jaw grading leads to vowel errors.  Some vowels are produced with the jaw low down (mouth is open) i.e. /ɑ/ (pot) and some are high jaw vowels i.e /ɛ/ (bed).  I work with many children that produce the high vowel in bed as bad.  Provide jaw support and teach the child to keep their jaw up.

  • Poor lip / jaw dissociation results in poor lip rounding and retraction which distorts many vowels.  Providing jaw support will help the child access their lips for those movements.

  • Consider facilitative context when choosing your target words.  Pair vowels and consonants that have similar jaw, lip or tongue movements.  i.e. the words "see" and "eat" are both produced with high jaw and elevated tongue.  The word bow may be easier then toe as both sounds in bow are produced with the lips.

When I choose my target words, I often start with the vowels that the child distorts.  I take the vowel, and I combine it with the consonants that the child can produce. I choose a toy that I can use to elicit that word.  i.e. if the child needs to work on the /ou/ vowel, I can choose from the words out, down, found, house, wow, etc.


Here is a link to download a free IPA vowel chart from Adventures in Speech Pathology. I use it all the time!

/æ/ cat /ɑ/ pot /ʊ/ book /i/ key /ɛ/ bed /ʌ/ bus /ɪ/ big

/eI/ gate /u/ blue /o/ coat /ai/ bye /aʊ/ wow 


Here is a link to a video demonstrating how I work with the vowel distortion in the word "truck".


And here is another video demonstrating difficulty with the word "on"


Here is a link to a REEL showing my power word resource from my Toys and Tools in Apraxia therapy course.  I use the resource to found power words with the sounds that the child needs to work on in therapy.

Free Target Selection Handout for CAS

Learn how to choose target words for minimally verbal children, understand

multisensory cueing, and other do's and don'ts in apraxia therapy.