Phonological Processes Chart: Ages When Each Pattern Should Stop

✓ Reviewed against ASHA Selected Phonological Patterns, ASHA Practice Portal, Dodd et al. (2003), Storkel (2022)Evidence level ALast reviewed October 14, 2026Published October 14, 2026

Phonological processes are the predictable ways young children simplify words — “tat” for “cat,” “top” for “stop,” “wabbit” for “rabbit.” They are normal, and each usually stops by a typical age: final-consonant deletion by about 3, fronting by about 4, gliding by 6–7. SLPs treat persistent or unusual ones.

What phonological processes are

Young children do not get adult words wrong at random. They simplify them in predictable ways — replacing a whole class of sounds with an easier one, dropping a sound from the end of a word, or squeezing a cluster down to one consonant. Speech-language pathologists call these phonological processes or phonological patterns. ASHA describes them as patterns young children commonly demonstrate that usually resolve as children get older.¹

The distinction from an articulation error matters. ASHA describes articulation disorders as difficulties with the motor production of speech sounds, and phonological disorders as difficulties with the linguistic aspects — the sound patterns of the language. A process is a rule a child is applying to many words at once, which is why fixing one word rarely fixes the pattern.²

📝

Dialects are not processes

ASHA is explicit that dialectal varieties that do not produce certain sounds are not error patterns. A child who sounds like the adults in their community is not using a phonological process.

The phonological processes chart

ASHA groups the common developmental processes into three families and gives a likely age of elimination for each — the age by which the pattern usually stops. ASHA’s ages draw on three clinical references (Bowen 2011; Peña-Brooks & Hegde 2015; Shipley & McAfee 2016), and the list is not exhaustive.¹

Common phonological processes, examples, and likely age of elimination (ASHA, Selected Phonological Patterns).
Process	What happens	Example	Likely age of elimination
Velar assimilation	A sound changes to K or G because of a nearby K or G	“kak” for “tack,” “guck” for “duck”	3
Nasal assimilation	A sound changes to a nasal because of a nearby nasal	“money” for “funny,” “nunny” for “bunny”	3
Fronting	A back sound (K, G) is replaced by a front sound (T, D)	“tat” for “cat,” “date” for “gate”	4
Stopping	A fricative or affricate is replaced by a stop	“pun” for “fun,” “tee” for “see,” “dump” for “jump”	F, S: 3 · Z, V: 4 · SH, CH, J, voiced TH: 5
Gliding	R or L is replaced by W or Y	“wabbit” for “rabbit,” “yeyo” for “yellow”	6–7
Deaffrication	CH or J is replaced by a fricative	“ship” for “chip,” “zhob” for “job”	4
Cluster reduction	A consonant cluster is simplified to one consonant	“top” for “stop,” “keen” for “clean”	With S: 5 · Without S: 4
Weak-syllable deletion	An unstressed syllable is dropped	“nana” for “banana,” “tato” for “potato”	4
Final-consonant deletion	The last consonant of a word is dropped	“bu” for “bus,” “no” for “nose”	3

Common phonological processes, examples, and likely age of elimination (ASHA, Selected Phonological Patterns).¹

The same chart, by age

Read the other way round, ASHA’s ages give a rough timetable of what a child is expected to have outgrown at each birthday.¹

Processes grouped by their likely age of elimination (ASHA, Selected Phonological Patterns).
Usually gone by about…	Processes
3	Final-consonant deletion · velar assimilation · nasal assimilation · stopping of F and S
4	Fronting · deaffrication · weak-syllable deletion · cluster reduction without S · stopping of Z and V
5	Cluster reduction with S · stopping of SH, CH, J, and voiced TH
6–7	Gliding (W for R, W or Y for L)

Processes grouped by their likely age of elimination (ASHA, Selected Phonological Patterns).¹

These are typical ages, not deadlines. ASHA cautions that the age at which patterns resolve varies greatly from child to child — especially for children who use more than one dialect. A UK normative study of 684 children aged 3;0 to 6;11 likewise found that error patterns fell away steadily with age, with no significant effect of socio-economic status.^1,3

Typical, persistent, or atypical?

ASHA draws the line clearly: phonological patterns that persist past their usual age, or patterns that are atypical, lead to a diagnosis of phonological disorder. “Atypical” means a pattern that is not among the common developmental ones on the chart above — for example, swapping front sounds for back ones (K for T) across the board.¹

Persistent: a process from the chart that is still going strong well past its age.
Atypical: a pattern that is not on the list of common developmental processes.
Many at once: several processes together, which can make a child very hard to understand.

Speech sound disorders are common. ASHA’s Practice Portal reports estimates of 2.1%–23% of 4- to 6-year-olds, depending on the study, and 3.6% of 8-year-olds with persistent speech sound disorders.²

How SLPs treat phonological processes

Because a process is a rule, treatment targets the rule rather than one sound at a time. ASHA lists several contrast approaches built for this — minimal pairs, maximal oppositions, and multiple oppositions — alongside the cycles approach, which works through phonological patterns in timed rotations for children with highly unintelligible speech.²

Which contrast approach suits which child (Storkel, 2022).
Approach	How it works	Best suited to
Conventional minimal pairs	Pairs differing by one sound (“key” vs. “tea”)	Children with a small number of errors — older children or mild disorders
Maximal oppositions	Pairs differing on many features at once	Children with multiple errors across multiple sound classes
Multiple oppositions	One error sound contrasted with several targets at once	Children who use one sound for many (a “phoneme collapse”) that hurts intelligibility

Which contrast approach suits which child (Storkel, 2022).⁴

The evidence base is wide but uneven. A review of 134 intervention studies identified 46 distinct intervention approaches, each with different amounts and levels of evidence; treatment was typically delivered by an SLP one-to-one, in 30- to 60-minute sessions two to three times a week. A UK survey found that speech discrimination, minimal pairs, and phonological awareness work were the most commonly used approaches, and noted that traditional articulation therapy has been found less effective for phonological difficulties.^5,6

Guides to each process

Each process has its own guide: what it sounds like, the typical age it stops, how SLPs work on it, and practice ideas for home.

Fronting — “tat” for “cat”
Stopping — “pun” for “fun”
Gliding — “wabbit” for “rabbit”
Cluster reduction — “top” for “stop”
Final-consonant deletion — “bu” for “bus”
Deaffrication — “ship” for “chip”
Weak-syllable deletion — “nana” for “banana”
Assimilation — “goggy” for “doggy”
The cycles approach — treating patterns in rotations

Free Speech Milestone Checker

Check which sounds your child should have by now — in 2 minutes.

Try it free →

When to get an evaluation

A process is still frequent well past its age on the chart.
Your child uses a pattern that is not on the chart.
Several processes are happening together and your child is hard to understand.
Your child is frustrated about not being understood.

ASHA’s early-identification guidance names being hard to understand, even to people who know the child well, as a sign of a speech sound disorder in young children. Children who have trouble producing speech sounds correctly may have a speech disorder; find a certified speech-language pathologist through ASHA’s ProFind directory.^8,9,7,10

Frequently asked questions

What are phonological processes?＋

Phonological processes (also called phonological patterns) are systematic simplifications young children make to adult words — swapping a whole class of sounds, dropping parts of syllables, or copying one sound onto another. Examples are “tat” for “cat” (fronting) and “top” for “stop” (cluster reduction). ASHA notes that they usually resolve as children get older.

At what age should phonological processes stop?＋

It depends on the process. ASHA’s table gives likely ages of elimination of about 3 for final-consonant deletion and assimilation; about 4 for fronting, deaffrication, weak-syllable deletion, and clusters without S; about 5 for clusters with S; between 3 and 5 for stopping, depending on the sound; and 6–7 for gliding. Ages vary from child to child.

What is the difference between a phonological process and an articulation error?＋

ASHA describes articulation disorders as difficulties with the motor production of speech sounds, and phonological disorders as difficulties with the linguistic, rule-based side — the patterns. An articulation error is usually a single sound made the wrong way (a lisp on S); a phonological process affects a group of sounds in a predictable way (every K and G becomes T and D).

When is a phonological process a problem?＋

ASHA states that phonological patterns that persist past their usual age, or patterns that are atypical — not among the common developmental ones — lead to a diagnosis of phonological disorder. Several processes at once, or speech that is hard to understand, are also reasons for an evaluation.

Is it a phonological process if it is just my child’s dialect?＋

No. ASHA is explicit that dialectal varieties of a language that do not produce certain sounds are not error patterns, and SLPs do not use these labels for dialect rules. Its own example: a Spanish-speaking child who does not produce final /s/ in their dialect is not showing final-consonant deletion.