Speech Sound Assessment Tests: The Measures SLPs Use and What the Scores Mean
A speech sound assessment uses several measures, not one test. Standardized picture-naming tests such as the GFTA-3, Arizona-4, or DEAP compare a child with same-age peers; a speech sample gives the percentage of consonants correct (PCC); intelligibility, stimulability, and perception tasks complete the picture.
The measures in a speech sound assessment
ASHA describes a speech sound assessment as a mix of standardized and nonstandardized, formal and informal measures, sampling speech in single words and in connected speech. Each measure answers a different question.1
| Measure | Question it answers | How results appear |
|---|---|---|
| Standardized single-word test (e.g., GFTA-3, Arizona-4) | How does this child compare with same-age peers on a fixed set of words? | Standard scores and a list of error sounds by word position |
| Connected speech sample | How does the child sound in real talk? | Transcription and error analysis |
| Percentage of consonants correct (PCC) | How severe are the errors overall? | A percentage, placed on a mild-to-severe continuum |
| Error-pattern analysis | Are errors random sounds or rule-based patterns, and are they consistent? | Named patterns (fronting, stopping) and consistency notes |
| Intelligibility rating | How much do listeners understand? | A rating scale or percentage of words understood |
| Stimulability testing | Can the child copy the sound with a model? | Stimulable or not, by level (sound, syllable, word) |
| Speech perception tasks | Can the child hear the difference between the target and their error? | Results on discrimination or identification tasks |
Measures used in speech sound assessment (ASHA Practice Portal; test names from MedlinePlus).1,2
Standardized tests and standard scores
MedlinePlus lists the Goldman-Fristoe Test of Articulation 3 and the Arizona Articulation and Phonology Scale among tools used to identify speech disorders; research studies such as a UK literacy cohort have used the Diagnostic Evaluation of Articulation and Phonology (DEAP). These tests have a child name pictures that elicit most consonants in different word positions.2,3,1
Their scores compare a child with a normative sample. Research cut-offs show how that works: one community study counted a 4-year-old as having a speech sound disorder if they scored 1 standard deviation or more below the mean on a standardized speech test, raised a researcher’s concern, or made three or more errors on sounds typically acquired by 4.4
The fairness caveat
ASHA states that standard scores cannot be reported for assessments not normed on a group representative of the child, and that a disorder is judged by the rules of the child’s own languages and dialects — not by comparison to mainstream American English.
This is why a good report describes your child’s speech in words, not just numbers.1
PCC and intelligibility
To calculate PCC, the SLP transcribes a speech sample, counts the total consonants, and counts how many were correct. ASHA describes it as a quantitative way to rate severity from mild to severe; one UK study used a PCC more than 2 standard deviations below the age mean — 85% at age 5½ in that test’s norms — as its cut-off for a speech sound disorder.1,3
Intelligibility is a listener’s judgment of how much is understood, rated on scales (for example, from “not at all” to “always”) or as a percentage of words understood. For context, ASHA cites average single-word intelligibility to unfamiliar listeners in typical children of 50% at 31 months, 75% at 49 months, and 90% at 83 months.1,5
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Questions to ask about the results
- Which sounds and patterns are in error, and which are typical for my child’s age?
- Are the errors consistent, or does the same word change from try to try?
- Is my child stimulable for the target sounds?
- Were the test norms a fair match for my child’s language and dialect?
- Did the assessment include hearing and language?
ASHA notes an assessment may end in a diagnosis, a decision that speech is appropriate for the child’s age and community, recommendations for treatment targets, or referrals. If you want a second opinion, find a certified SLP through ASHA’s ProFind directory.1,6
About SpeechStep
SpeechStep’s free checks are screeners, not standardized tests, and produce no standard scores. Practice gives an instant AI check for R and listen-and-compare for other sounds.
Frequently asked questions
What tests are used for a speech sound assessment?＋
Usually a standardized single-word test plus other samples. MedlinePlus lists tools such as the Goldman-Fristoe Test of Articulation 3 (GFTA-3) and the Arizona Articulation and Phonology Scale (Arizona-4); research studies also use the Diagnostic Evaluation of Articulation and Phonology (DEAP). ASHA describes combining standardized tests with conversation samples and criterion-referenced measures.
What is PCC in speech?＋
Percentage of consonants correct: the SLP transcribes a speech sample, counts all the consonants, and calculates the share produced correctly. ASHA describes PCC as a quantitative way to place severity on a continuum from mild to severe.
What does a standard score on an articulation test mean?＋
It compares your child with the test’s normative sample of same-age children. ASHA cautions that standard scores cannot be reported for tests not normed on a group representative of the child — for example, a child who speaks another dialect or language.
Is one test enough to diagnose a speech sound disorder?＋
No. ASHA notes that single-word testing may not reflect how a child sounds in connected speech, so assessments add a conversation sample, intelligibility judgments, and stimulability testing. Telling a severe speech sound disorder apart from childhood apraxia of speech needs a combination of measures.
Put this into practice today
Try the free lisp check, or start daily AI speech practice — every child takes one SpeechStep at a time.
References
6 sources from authoritative bodies. Last reviewed October 2026.
- 1.ASHASpeech Sound Disorders: Articulation and Phonology — Practice Portal page.
- 2.MedlinePlus (U.S. National Library of Medicine)Speech disorders - children — Medical encyclopedia.
- 3.Peer-reviewedHayiou-Thomas, Carroll, Leavett, Hulme & Snowling — When Does Speech Sound Disorder Matter for Literacy? — Longitudinal cohort study (Journal of Child Psychology and Psychiatry), 2017.
- 4.Peer-reviewedTtofari Eecen, Eadie, Morgan & Reilly — Validation of Dodd’s Model for Differential Diagnosis of Childhood Speech Sound Disorders — Community cohort study (Developmental Medicine & Child Neurology), 2019.
- 5.Peer-reviewedHustad et al. — Speech Development Between 30 and 119 Months in Typical Children I: Intelligibility Growth Curves — Normative study (JSLHR), 2021.
- 6.ASHAASHA ProFind: Find a Certified Speech-Language Pathologist — Referral directory.