Why Can My Child Say the Words Clearly Yet Still Sound So Unclear in Sentences?

Your child can say dinner.

They can say want.

They can say my.

You've heard each of those words clearly.

But then they try to say:

"I want my dinner."

...and suddenly their speech is much harder to understand.

This is something I see frequently in children with Childhood Apraxia of Speech (CAS), particularly as they move into the mid-to-later stages of therapy.

It can feel confusing.

If a child has learnt to say the individual words clearly, why can't they simply put those words together?

The answer is that speaking in sentences isn't simply a matter of placing a series of mastered words next to one another.

It creates an entirely new motor planning challenge.

Therapy Often Starts Small

In the earlier stages of CAS therapy, much of our work focuses on helping children develop increasingly accurate syllable shapes and words.

We might start with simple word shapes such as:

CV Words

• me

• no

• do

VC Words

• up

• out

CVC Words

• mum

• pop

• top

CVCV Words

• puppy

• mummy

• baby

Over time, we build a larger bank of syllable shapes and increasingly complex words.

A child may become very good at producing these words individually. Their speech can begin to sound considerably clearer at the single-word level.

But everyday communication doesn't happen one word at a time.

We speak in sentences.

And suddenly the speech motor system is being asked to do something much more difficult.

Sentences Are a Much Bigger Motor Challenge

Take the simple sentence:

"I want my dinner."

That's already five syllables that need to be planned, sequenced and produced together.

Or consider:

"Pass me the tomato, please."

A child may be able to say tomato beautifully as a single-word target.

But now we've embedded that word within a seven-syllable utterance.

The motor planning load has increased significantly.

The child isn't simply retrieving a series of words they already know.

Their speech system now has to coordinate a much longer sequence of movements while transitioning smoothly from one syllable and one word into the next.

That is why a child may produce a word clearly in isolation but lose some of that accuracy when the same word appears within a longer phrase or sentence.

Importantly, I don't necessarily see this as a sign that therapy isn't working.

It can be a very normal part of CAS therapy and often indicates that we're ready to begin scaffolding the transition from clear individual words to longer, connected utterances.

What Can Happen When We Make the Utterance Longer?

Sometimes overall intelligibility drops even though it's difficult to immediately identify why.

There are several things I commonly listen for when this happens.

1. Extra Sounds Can Creep In

Some children insert sounds that don't belong in the word.

For example, a child might say:

"wornd" instead of "word"

or add an unnecessary sound at the beginning, middle or end of another word.

At the single-word level they may have been able to maintain the movement sequence accurately.

Once that word becomes one small part of a much longer motor sequence, those extra movements can appear again.

When this happens, I don't immediately abandon the sentence and return completely to single-word therapy.

Instead, I might:

• slow things down

• model the movement

• segment part of the utterance

• temporarily reduce its complexity before building it back up.

  
  

2. Vowel errors may reappear

A vowel that sounded accurate in an individual word can sometimes become less accurate when the child has to produce that word within a longer utterance.

Again, this makes sense when we think about the increased motor demands.

The child is now coordinating multiple movements in rapid succession rather than concentrating all of their motor planning on one word.

With targeted practice at the multisyllabic word, phrase and sentence level, these vowel patterns can become increasingly stable.

3. Consonant blends can become particularly challenging

Consonant blends require the child to move from one consonant directly into another before reaching the vowel.

Think about the word:

stop

The child has to transition smoothly from:

/s/ → /t/ → vowel

For some children with CAS, these rapid transitions remain challenging even when many other aspects of their speech have become much clearer.

Blends can occur:

• at the beginning of words

• within words

• at the ends of words

• across word boundaries.

  
  

At the sentence level, I may therefore provide additional support for these transitions rather than assuming that because the child can produce both individual sounds, they will automatically be able to sequence them together.

4. “Slippery sounds” can become less stable

Glides and liquids, such as:

• /l/

• /r/

• /w/

• /j/

require smooth, continuous and highly coordinated movements of the tongue and mouth.

I sometimes think of these as “slippery sounds” because of the amount of movement coordination involved.

A child may produce them successfully in some words but find them much more difficult to maintain as their utterances become longer and more complex.

Clear sentences are not simply clear words placed next to one another

This is one of the most important things to understand about sentence-level CAS therapy.

Natural speech flows.

We don’t usually pronounce every word in a sentence as though we’re reading it individually from a flashcard.

Imagine saying:

“The. Car. Is. Here.”

with a deliberate pause between every word.

It sounds robotic.

Now say naturally:

“The car is here.”

Notice how your mouth keeps moving. Sounds flow into one another. Some sounds become less prominent. Vowels may become more neutral. The end of one word helps carry us into the beginning of the next.

Most children learn these patterns without anyone explicitly teaching them.

Children with CAS may not.

Sometimes we actually need to teach them how to join the words together.

Sometimes we need to teach the “hidden” sounds between words.

These linking movements are often so automatic for adults that we don't even realise we are producing them.

When we speak naturally, we sometimes use sounds or movements between words that aren’t obvious from looking at the written sentence.

These little bridges help our speech sound smooth and natural rather than choppy or robotic.

For example, in Australian English, the /r/ at the end of a word such as car isn’t generally pronounced when the word is said alone.

But listen to what happens when we say:

“The car is here.”

The movement between car and is changes because we’re linking one word into the next.

Other sentences may involve subtle /j/, /w/ or other linking movements between words.

For a child whose motor speech system is already working very hard to plan a sentence, these transitions may not simply appear automatically.

We may need to make the invisible visible.

Listen closely to how YOU say the sentence

This is something I encourage speech pathologists to do all the time.

Before asking a child with CAS to produce a difficult sentence, say it naturally to yourself.

Not the way you think the words should be pronounced.

The way you actually say them in conversation.

Listen carefully:

• How does your mouth move from one word into the next?

• Where do the words blend together?

• Which vowels become less prominent?

• Where does the stress naturally fall?

• Are there sounds or movements appearing between words?

• Are you accidentally modelling every vowel too perfectly because you’re concentrating on speaking clearly?

  
  

These tiny details can give us important clues about why a child is struggling and what we may need to explicitly teach.

We don’t always want perfect vowels

This can initially sound counterintuitive in CAS therapy.

In the earlier stages of therapy, I often work hard to eliminate intrusive schwa errors — for example, a child adding an unnecessary “uh” and changing the syllable structure of a word.

But later, when we’re working toward natural connected speech, there are situations where a more neutral or schwa-like vowel is exactly what we need.

In conversational speech, many vowels naturally become reduced.

If we insist that a child pronounce every vowel with the same clarity and emphasis they used when learning the individual word, their sentences can become effortful and unnatural.

Some children with CAS need explicit teaching to reduce that effort and allow their speech to become smoother, faster and more conversational.

This is another reason sentence-level therapy isn’t simply 

“say all your clear words one after another.”

We’re teaching a different level of speech motor skill.

So how do we move from clear words to clear sentences?

Usually, I don’t jump straight from a successful word to a long sentence.

I scaffold it.

If a child can produce a word accurately and relatively easily, I might add another word or two and see what happens.

Then another.

We gradually increase the motor planning load while trying to preserve the movement pattern the child has already learnt.

For example, we might move from:

boot

to:

gumboot

to:

my gumboot

to:

I want my gumboot

The exact progression will depend on the individual child.

Sometimes I use backward chaining.

Sometimes I segment part of the sentence and gradually blend it back together.

Sometimes I slow my model.

Sometimes I provide additional support for one particularly difficult transition.

And sometimes I realise I’ve increased the complexity too quickly and simply step back.

This is the part of CAS therapy that is difficult to capture in a set of rigid rules.

We’re constantly watching the child, listening to their production and deciding:

What is making this difficult — and what small change might help them succeed?

See It In Action

This short video demonstrates one of the key ideas discussed in this article: a child may produce a word accurately in isolation but require additional support as that same movement pattern is embedded into longer phrases and sentences.

▶ Watch the reel below

The goal isn’t just clear words. It’s clear communication.

Getting a previously difficult word clear is worth celebrating.

It tells us that the child’s speech motor system is learning.

But ultimately, children don’t communicate in isolated therapy words.

They tell us what happened at school.

They ask for what they want.

They argue with their siblings.

They tell jokes.

They explain complicated ideas.

They talk.

So once individual words are becoming clearer, our job is to help those increasingly accurate movement patterns survive longer words, more complex syllable shapes, phrases, sentences and eventually spontaneous connected speech.

If your child can say many words clearly but still becomes difficult to understand when they start talking in sentences, it doesn’t mean all that work at the word level has been wasted.

Those clear words are the foundation.

Now it’s time to teach their speech motor system how to put it all together.

Wondering Whether Your Child Might Have Childhood Apraxia of Speech?

If your child is easier to understand in single words than sentences, struggles with longer utterances, or speech seems to become less clear as they talk more, a comprehensive assessment can help identify whether Childhood Apraxia of Speech (CAS) may be contributing to these difficulties.

Want to learn more about Childhood Apraxia of Speech?

👉 Complete my free CAS Screener

👉 Listen to my podcast episode: Apraxia Treatment Series: Part 2 (Sentences & Multisyllabic Words)

👉 Join the CAS Academy waitlist (for speech pathologists)