Categories: Speech development
anna blee speech pathologist

Anna Blee

Anna is a passionate Speech Pathologist who works with small children and makes them feel special and celebrated as they tackle challenges.


Speech-Language Pathologists, as the name suggests, can work with both speech and language. Speech refers to the sounds within a language system. Language refers to both understanding (receptive) and conveying (expressive) meaning. We can also provide support in pragmatics which is the way in which language is understood and used for social purposes (including both verbal and non-verbal means). This blog will teach you about ‘Phonology’, which is a component of speech development and applies to sounds within words. In this blog, we will explore the concept of phonological processes, their types, and their significance in speech development and acquisition.

Phonological processes are a natural part of speech development and are present in all languages. These processes should resolve at particular ages though, and these ages are influenced by the frequency that sounds appear within a given language (for example Mandarin speakers acquire adjacent consonants and affricate sounds like ‘ch’ and ‘j’ much earlier than English speakers, as these occur much more frequently in their language system – fascinating right?!) All children use these patterns of sound omission or substitution as they acquire more complex motor patterns.

Types of Phonological Processes

There are several types of phonological processes that occur in speech, including assimilation, substitution, deletion, and addition.

Assimilation is a process in which a sound changes to become more like a neighbouring sound. For example, children might say ‘ga’ instead of ‘car’ because the vowel requires that the child’s voice is ‘switched on’ and in anticipation of this, they voice the quiet sound ‘k’ at the start of the word.

Substitution is a process in which one sound is replaced by another sound. For example, children will often replace ‘r’ with ‘w’ at early ages, saying ‘wed’ instead of ‘red’.

Deletion is a process in which a sound is omitted from a word. This can occur at the end of words commonly, but in less cases in the middle or at the start of words also. Leaving sounds off at the start of words can be considered a risk-factor for more complex speech-sound difficulties. E.g. ‘ister’ for ‘sister’.

Addition is a process in which a sound is added to a word. This is again a less common pattern, but it can occur in complex speech disorders.

Significance of Phonological Processes in Language Development and Acquisition

Phonological processes play a critical role in the diagnosis and treatment of speech disorders. When a child is diagnosed with a speech disorder, the therapist will often assess the child’s use of phonological processes to identify the specific areas of difficulty.

For example, if a child is diagnosed with a phonological disorder, the therapist may identify that the child is consistently omitting sounds from words or substituting one sound for another. By targeting these specific phonological processes, the therapist can help the child to improve their ability to produce accurate and clear speech. Phonological therapy differs from the therapy that would be used for a child who has articulation errors (where the target sound is not able to be produced in any position in words), motor-based speech difficulties like motor-speech delay or dysarthria, or in neurologically based difficulties such as Apraxia of speech. Differential diagnosis is crucial to your Speech Pathologist selecting the most evidence-based and efficient therapy techniques for your child. Assessing for inconsistency across multiple productions of the same word might also be required.

If you have concerns about the patterns your child is using within their sound system, it’s always best to have them assessed by a Speech-Language Pathologist.

If you wish to explore this topic further, you can check out the following websites: