The Different Phonological Processes (List for SLPs)

Speech pathologists working with younger children will very likely treat phonological disorders. Part of the process of correcting phonology errors involves understanding the different phonological processes, or speech pattern simplifications, that children may use. This article explains the most common phonological processes and provides examples for SLPs.


What is a Phonological Disorder?

Phonological errors are patterns of sound errors that are rule-based and impact more than one sound. A phonological disorder falls under the umbrella of a ‘speech sound disorder’. A child who has a phonological disorder may consistently exhibit phonological processes in his speech, such as fronting, cluster reduction, stopping, or final consonant deletion.

How is a Phonological Disorder Diagnosed?

It is within the scope of a speech-language pathologist to diagnose a phonological disorder. Often, clinical judgment, along with an assessment, is used. Assessments may be informal or formal. Many standardized assessments are able to provide severity rankings, as well as the overall percentage that a phonological process is exhibited by a student. This can be very useful for goal setting.

Assessments I have personally used include the CAAP-2 (Clinical Assessment of Articulation and Phonology- Second Edition) and the HAPP-3 (Hodson Assessment of Phonological Patterns- Third Edition).

Phonological processes that are observed 40% of the time or higher are considered to be active phonological processes. In my professional opinion, any process that is observed at least 30% of the time or higher may be impacting intelligibility.

What are the types of phonological processes?

Phonological processes can be categorized as:

  • syllable structure processes
  • substitution processes
  • assimilatory processes

Syllable structure processes involve changes made to the syllable structure. Cluster reduction (i.e. “mile” for “smile”), reduplication (i.e. “wawa” for “water”) , weak syllable deletion (“nana” for “banana”), and final consonant deletion (“pih” for “pig”) fall under the umbrella of syllable structure processes.

Substitution processes involve changes, such as one sound class changing to another sound class. Changes may occur in place of articulation, manner of articulation, or voicing. Examples include fronting (“tall” for “call”), affrication (“chew” for “shoe”), and voicing (i.e. “doo” for “two”).

Assimilatory processes occur when a sound in a word changes to become more like a neighboring sound. Velar assimilation (“guck” for “duck”), labial assimilation (“fwing” for “swing”), nasal assimilation (i.e. “nunny” for “bunny”), and liquid assimilation (i.e. “lelo” for “yellow”) are examples of this.


Syllable Structure Processes

Cluster Reduction

Consonant cluster reduction occurs when a consonant is deleted from a cluster. Often, cluster reduction occurs on l blends, s blends, and r blends. Examples might include “pane” for “plane” or “mile” for “smile”.

*When s, l, or r are missing from the cluster, it is called ‘marked cluster reduction’.

Click here for cluster reduction minimal pairs.


Reduplication occurs when the first syllable of a word is repeated. An example of this might be saying ‘wawa’ for ‘water’. Typically, this process is extinguished by the age of 2 1/2.

Weak Syllable Deletion

Syllable deletion occurs when a syllable is omitted. Weak syllable deletion specifically involves the omission of an unstressed syllable. An example could include saying ‘nana’ for ‘banana’. SLPs will often target marking all syllables in multisyllabic words. Here is an activity that targets syllable deletion for use in speech therapy.

speech therapy smash mat articulation
multisyllabic words smash mat for speech therapy

Final Consonant Deletion

Final consonant deletion occurs when the final consonant of a word is omitted. Examples of this would be saying “pih” for “pig” or “kay” for “cake”. It is my professional opinion that voiceless final consonants are a great place to start when targeting final consonant deletion, or FCD.

Target final consonant deletion using this activity.

Substitution Processes

Consonant Cluster Substitution

This process occurs when one consonant sound in a cluster is substituted for another sound. Examples might include ‘stwing’ for ‘string’, or ‘gween’ for ‘green’. These examples could also be classified as gliding.

Velar Fronting

Velar fronting occurs when a sound made in the “back”, a velar sound (such as k, g, or ng) is replaced with a sound made in the “front” of the mouth, like an alveolar sound. Examples might include “doe” for “go” or “tall” for “call”. Try using these fronting minimal pairs in speech therapy.

Palatal Fronting

Palatal fronting occurs when a sound made in the back (a palatal sound, ‘sh’) occurs in the front (an alveolar sound, like ‘s’). The tongue should be touching the roof of the mouth, or the palatal area, to make the “sh” sound, but instead touches near the alveolar ridge. Examples might include saying “so” for “show” or “fis” for “fish”.


Labialization occurs when a labial sound (including bilabials, such as p, b, m, or labio-dental sounds, such as f or v) replaces a non-labial sound. An example of this would be saying “fum” for “thumb”.


Alveolarization occurs when sounds that are not alveolar sounds become alveolar sounds. Alveolar sounds include t, d, s, z, n, and l. They may be substituted with interdental sounds (voiced th, voiceless th) and labiodental sounds (which include f and v). An example of alveolarization would include saying “some” for “thumb”.


The phonological process of stopping occurs when a stop sound (such as p, b, t, d, k, or g) replaces a fricative (f, v, th, s, z, sh, zh) or an affricate (ch, dj). Examples might include saying “Pete” for “feet” or “fit” for “fish”.

Here is an activity that targets the phonological process of stopping.


Gliding occurs when liquid sounds (l, r) are substituted by glides (w, j). An example would be saying “wed” for “red”. Try out this free gliding activity in your speech therapy session.

Vocalization (also called Vowelization)

Vocalization (also known as vowelization) is a phonological process that involves the substitution of a vowel for a syllabic liquid or vocalic er. Examples would include “cah” for “car” or “laduh” for “ladder”. Check out more vocalic r tips.


Affrication is a phonological process that involves the replacement of a fricative sound (such as “sh”) with an affricate (such as “ch” or “dj”). An example of affrication would be “chew” for “shoe”.


Deaffrication is a phonological process that involves changing an affricate sound (“ch” or “dj”) to a stop (such as p, b, t, d) or a fricative (i.e. s, z, sh). An example might be “shop” for “chop” or “tear” for “chair”.


The phonological process of voicing occurs when a voiceless sound is used in place of a voiced sound. An example of voicing would be ‘big’ for ‘pig’. Try this voicing activity with your speech therapy students, or use these voicing and devoicing phonology play dough smash mats.


The phonological process of devoicing occurs when a voiceless sound is used in place of a voiced sound. An example of devoicing would be “pig” for “big”. These devoicing minimal pairs are very effective for targeting this process.


The phonological process of denasalization occurs when a nasal sound (m, n, ng) is replaced with a stop (p,b, t, d, k, g). For example, the nasal /m/ may be replaced by /p/ or /b/. An example might include “boo” for “moo”.


Assimilatory Processes

Labial Assimilation

The phonological process of labial assimilation occurs when a labial sound is changed into a non-labial sound. The non-labial sound is a neighboring sound in the word, and is “influenced” by the labial sound. Labial sounds may include bilabials (p,b,m) and labiodentals (f,v). An example would be “fwim” for “swim”.

Velar Assimilation

Velar assimilation is a phonological process that occurs when a nonvelar sound is influenced, and changed, by a neighboring velar sound. Velar sounds include k, g, and ng. An example of velar assimilation might be saying “kack” for “tack”. The velar /k/ influences the lingua- alveolar sound /t/ in this example.

Nasal Assimilation

Nasal assimilation is a phonological process that occurs when a non-nasal sound is influenced, and changed, by a neighboring nasal sound (m, n, j). For example, saying ‘money’ for ‘funny’ or ‘bunny’.

Liquid Assimilation

Liquid assimilation is a phonological process that occurs when a nonliquid sound is influenced, and changed, by a neighboring liquid sound. Liquid sounds include l and r. An example of liquid assimilation might be saying “lellow” for “yellow”.


Bauman-Waengler, J. A. (2012). Articulatory and phonological impairments. New York, NY: Pearson Higher Education.

Pena-Brooks, Adriana (2007). Articulation and Phonological Disorders: Assessment and Treatment Manual. Austin, Texas: Pro-Ed Inc.

“Selected Phonological Processes.” Selected Phonological Processes, American Speech-Language-Hearing Association, https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology/selected-phonological-processes/.