What are Phonological Processes?

phonological processes

Child Speech Development is based on Articulation (physically being able to say a sound) and Phonological Processes.

Phonological processes are the predictable sound rules or patterns that young children use to make saying words easier for them. “Phonological” (meaning sounds) and “processes” refers to the predictable sound changes that young children use.

phonological processes
For example, a lot of 18 month old children do not have the control over their tongues and lips enough to say the /t/ and the /r/ sound together in words like “truck”.

Instead they will use a phonological process such as “cluster reduction” to simplify the /tr/ cluster. This means they may reduce the /tr/ cluster to single sounds. The single sound may be the /t/ sound, or even a /f/ sound, instead of the /tr/ sounds. We all have probably heard a young child that has not mastered mature speech unintentionally say “truck” in a cringe worthy way!

Toddler speech sound development therefore involves children using different phonological processes at different ages.

​In typical development, the phonological processes used are largely predictable depending on the toddler’s age. As children get better motor control of their tongue and lips they say words more closely matching the “correct” adult form. Consequently, they use less and less phonological processes. By approximately 5 years of age, most children stop using all phonological processes and their speech sounds more like the adults around them. The less processes a child uses the clearer their speech.

​Do all children use all phonological processes?

There are lot of different types of phonological processes and not all children will use all phonological processes during their speech development journey. There are:

Developmental Phonological Processes

sound patterns that ALL typically developing children tend to use as their speech develops (e.g., 18-24 month old children often leave off the last sound in a word such as “ba_” for “bat”.

Non-Developmental Processes

sound patterns that would be considered atypical as most children will never or rarely use these processes. These types of processes are considered warning signs of speech disorders (e.g., leaving off the first sound in a word such as “_at” for “bat”).

Types of Phonological Processes

The types of phonological processes used by children are varied. All phonological processes aim to simplify how words are said. However, how the processes make the word easier to say is what varies. There are different types of phonological processes including:

  • Substitution Phonological Processes:  This is where children will replace one sound for another sound.

A process called “Fronting” is an example. This is where children will substitute sounds usually said with the back of the tongue (e.g., /k/ and /g/ sounds) with sounds that are said with the tip of the tongue (e.g., /t/ and /d/). Example: “key” is said as “tea” or “go” is said as “doe”.

  • Syllable Structure Phonological Processes:  These processes generally simplify words by using less syllables or sounds than the adult form of the word.

A process called Word-Final Deletion is one example of a syllable structure phonological process. Example: “bed” is said as “be_”.

Syllable structure Phonological Processes may also cause syllables to be repeated. Reduplication is an example. Example: “water” is said as “wa-wa”.

  •   Assimilation Processes:  This is where one sound in a word makes another sound in the word change.

A process called Pre-vocalic voicing is where a “soft’ sound (e.g, p, t, k) is substituted by a loud sound (e.g., b, d, g) at the beginning of a word before the vowel sound. Example: “key” is said as “gey”

What phonological processes are expected at the different ages.

phonological processes

There are developmental milestone charts that show what phonological process are appropriate at different ages. A FREE copy of such a chart is part of our Speech sound Developmental Checklist download.

​However, it can be very difficult for parents to work out exactly what phonological process a child is using.

​This is because there are a lot of different types of phonological processes and more than one phonological process may be used to simplify even one word! Some processes may be OK for a toddler’s age but other phonological processes can be inappropriate. Let’s look at an example.

​A child may try to say “stop” but it comes out as “Do_”
  1. ​/st/ -> t : Syllable structure reduces the word by a process called Cluster Reduction (stop -> top).
  2. Then the /t/ is affected by the vowel. The Pre-vocalic assimilation phonological process turns the /t/ into a /d/ (top -> Dop)
  3. The last sound /p/ is deleted with a word-final deletion (dop -> do_).

Speech Pathology speech assessments include identifying what phonological processes a child is using and determining if it appropriate for a child of that age to be using the phonological processes observed.

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