Speech Development: Why is it important, and what affects it?

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May 28
5 min read

Speech development is one of the most misunderstood areas of childhood development.

Many parents are told speech is simply about a child’s vocabulary, pronunciation, listening or intelligence. But speech is actually built on the development of the nervous system.

Before a child can speak clearly, organise language, communicate socially or process conversations, the brain has to develop through multiple foundational stages first.

Speech therapy session with child using flashcards and mirror at home

When those lower systems are immature, speech can be delayed, inconsistent, effortful or emotionally dysregulated.

As experts in learning support for children that focuses on the foundations, Brain Development knows how vital it is to look at a child’s cognitive development.

What Affects Speech Development?

1. Primitive Reflexes

Primitive reflexes are automatic survival reflexes present in infancy. These reflexes should naturally integrate during early development as higher brain systems mature.

If they remain active, they can interfere with speech and language development.

Common reflexes linked to speech difficulties include:

The Rooting Reflex

The rooting reflex helps babies find the breast or bottle. If retained, children may struggle with drool, chew clothing, mouth objects, have unclear articulation, struggle with feeding or have poor tongue coordination.

Children may also become orally fixated or seek objects for constant chewing.

Moro Reflex

The Moro reflex is the body’s startle reflex. If retained, speech can be affected because the nervous system stays in a heightened stress state.

These children may:

freeze when asked questions
struggle to retrieve words
become overwhelmed in conversation
have emotional outbursts
appear anxious socially
struggle in noisy environments

Unfortunately, a stressed brain does not communicate efficiently.

ATNR (Asymmetrical Tonic Neck Reflex)

This reflex links the turning of the head with arm movements.

When retained, it can interfere with:

crossing midline
bilateral coordination
eye tracking,
reading and writing,
auditory processing
sequencing language

Speech is not just talking: it is sequencing, timing, rhythm and coordination.

STNR (Symmetrical Tonic Neck Reflex)

This reflex helps babies transition into crawling.

If retained, children often struggle with their posture, sitting still, focusing visually, hand-eye coordination, maintaining attention and timing their speech normally. Because posture and breathing affect speech production, a poor posture often impacts communication.

Vestibular Development

The vestibular system is the brain’s balance and movement system. It helps organise balance, posture, eye movements, coordination, attention, auditory processing and the timing of speech.

Children with vestibular immaturity may:

struggle to follow instructions,
lose words when overwhelmed,
become fatigued listening,
have delayed processing,
struggle with reading,
avoid group conversation,
or have poor expressive language.

The vestibular system is deeply connected to the cerebellum, which helps coordinate speech rhythm and timing.

This is why movement therapies often help language development.

The Cerebellum

The cerebellum is often called the “coordination centre” of the brain. But it does much more than help control our movements.

The cerebellum also helps coordinate the timing of language and rhythm of speech, emotional regulation, sequencing, sense of social timing and emotional regulation.

Children with cerebellar immaturity may speak too quickly, struggle to organise their thoughts and pause excessively. You might also notice they lose words, stumble over speech or become dysregulated socially.

Speech requires incredibly precise timing between multiple systems in the brain.

Nervous System Regulation

A child who feels unsafe cannot access speech efficiently.

When the nervous system is stuck in fight, flight, freeze or shutdown. It’s important to remember the brain prioritises survival over communication. This is why many children:

speak less in stressful environments
communicate well at home but not school
lose the ability to speak under pressure
Often appear socially withdrawn.

Speech is strongly linked to autonomic nervous system regulation. This is also why emotional safety matters so much.

5. Sensory Processing

Speech relies heavily on sensory integration.

Children must process:

sound
body awareness
movement
touch
visual input
and social information simultaneously.

If sensory systems are overloaded, communication becomes harder.

For example:

auditory hypersensitivity may make language difficult in noisy rooms,
tactile defensiveness can affect oral motor control,
proprioceptive difficulties can reduce awareness of tongue and mouth positioning,
vestibular instability can affect attention and speech organisation.

Sometimes what appears to be a “speech issue” is actually a sensory regulation issue.

6. Oral Motor Development

Speech requires precise coordination of the lips and tongue, jaw and cheeks.

Children with oral motor immaturity may struggle to pronounce sounds, mumble or become fatigued while speaking. You might also notice they chew excessively, prefer soft foods, gag easily or avoid certain textures,

Looking at their history with food during the early years can often provide important clues.

7. Breathing & Vagus Nerve Function

Breathing patterns strongly influence speech.

Children who mouth breathe or remain in chronic stress often have shallow breathing, less control over their vocals, softer voices or dysregulated speech patterns.

The vagus nerve plays a major role in vocal tone, social engagement, emotional regulation and autonomic balance.

This is why vagal stimulation activities can sometimes improve communication and social interaction.

8. Right and Left Brain Development

Speech is not controlled by one single area of the brain. Different parts of communication are processed by different hemispheres.

The Left Hemisphere Helps With:

speech production,
grammar,
sequencing,
phonics,
word retrieval.

The Right Hemisphere Helps With:

social communication,
emotional tone,
facial expression,
understanding humour,
body language,
conversational rhythm.

Some children can speak very well mechanically but struggle socially. Others understand socially but struggle with language organisation.

Both hemispheres need to work together for mature communication.

9. Gut Health, Inflammation & Stress

The gut and brain are deeply connected.

Children experiencing:

food sensitivities,
chronic inflammation,
poor sleep,
mould exposure,
nutritional deficiencies,
or chronic stress,

often show changes in:

attention,
emotional regulation,
auditory processing,
and speech.

The brain develops best when the body feels safe and regulated.

Speech Is Developmental, Not Just Educational

One of the most important things parents can understand is this:

Speech is not simply “taught.” It emerges from the development of the nervous system.

A child may know exactly what they want to say but struggle because:

their brain is overloaded
their body feels unsafe
reflexes are immature
sensory systems are dysregulated

When we support regulation, the way they move, vestibular development, primitive reflex integration, sensory processing and emotional safety, communication often improves naturally.

Signs A Child May Need Foundational Support

Here at Brain Development we focus on providing the support children need to thrive. Some common signs your child could benefit from brain foundational support include: