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Speech Sound Disorders-Articulation and Phonology

See the Assessment section of the Speech Sound Disorders Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.


Screening is conducted whenever a speech sound disorder is suspected or as part of a comprehensive speech and language evaluation for a child with communication concerns. The purpose of the screening is to identify individuals who require further speech-language assessment and/or referral for other professional services.

Screening typically includes

  • screening of individual speech sounds in single words and in connected speech (using formal and or informal screening measures);
  • screening of oral motor functioning (e.g., strength and range of motion of oral musculature);
  • orofacial examination to assess facial symmetry and identify possible structural bases for speech sound disorders (e.g., submucous cleft palate, malocclusion, ankyloglossia); and
  • informal assessment of language comprehension and production.

See ASHA's resource on assessment tools, techniques, and data sources.

Screening may result in

  • recommendation to monitor speech and rescreen;
  • referral for multi-tiered systems of support such as response to intervention (RTI) ;
  • referral for a comprehensive speech sound assessment;
  • recommendation for a comprehensive language assessment, if language delay or disorder is suspected;
  • referral to an audiologist for a hearing evaluation, if hearing loss is suspected; and
  • referral for medical or other professional services, as appropriate.

Comprehensive Assessment

The acquisition of speech sounds is a developmental process, and children often demonstrate "typical" errors and phonological patterns during this acquisition period. Developmentally appropriate errors and patterns are taken into consideration during assessment for speech sound disorders in order to differentiate typical errors from those that are unusual or not age appropriate.

The comprehensive assessment protocol for speech sound disorders may include an evaluation of spoken and written language skills, if indicated. See ASHA's Practice Portal pages on Spoken Language Disorders and Written Language Disorders.

Assessment is accomplished using a variety of measures and activities, including both standardized and nonstandardized measures, as well as formal and informal assessment tools. See ASHA's resource on assessment tools, techniques, and data sources.

SLPs select assessments that are culturally and linguistically sensitive, taking into consideration current research and best practice in assessing speech sound disorders in the languages and/or dialect used by the individual (see, e.g., McLeod et al., 2017). Standard scores cannot be reported for assessments that are not normed on a group that is representative of the individual being assessed.

SLPs take into account cultural and linguistic speech differences across communities, including

Consistent with the World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF) framework (ASHA, 2016a; WHO, 2001), a comprehensive assessment is conducted to identify and describe

  • impairments in body structure and function, including underlying strengths and weaknesses in speech sound production and verbal/nonverbal communication;
  • co-morbid deficits or conditions, such as developmental disabilities, medical conditions, or syndromes;
  • limitations in activity and participation, including functional communication, interpersonal interactions with family and peers, and learning;
  • contextual (environmental and personal) factors that serve as barriers to or facilitators of successful communication and life participation; and
  • the impact of communication impairments on quality of life of the child and family.

See ASHA's Person-Centered Focus on Function: Speech Sound Disorder [PDF] for an example of assessment data consistent with ICF.

Assessment may result in

  • diagnosis of a speech sound disorder;
  • description of the characteristics and severity of the disorder;
  • recommendations for intervention targets;
  • identification of factors that might contribute to the speech sound disorder;
  • diagnosis of a spoken language (listening and speaking) disorder;
  • identification of written language (reading and writing) problems;
  • recommendation to monitor reading and writing progress in students with identified speech sound disorders by SLPs and other professionals in the school setting;
  • referral for multi-tiered systems of support such as response to intervention (RTI) to support speech and language development; and
  • referral to other professionals as needed.

Case History

The case history typically includes gathering information about

  • the family's concerns about the child's speech;
  • history of middle ear infections;
  • family history of speech and language difficulties (including reading and writing);
  • languages used in the home;
  • primary language spoken by the child;
  • the family's and other communication partners' perceptions of intelligibility; and
  • the teacher's perception of the child's intelligibility and participation in the school setting and how the child's speech compares with that of peers in the classroom.

See ASHA's Practice Portal page on Cultural Competence for guidance on taking a case history with all clients.

Oral Mechanism Examination

The oral mechanism examination evaluates the structure and function of the speech mechanism to assess whether the system is adequate for speech production. This examination typically includes assessment of

  • dental occlusion and specific tooth deviations;
  • structure of hard and soft palate (clefts, fistulas, bifid uvula); and
  • function (strength and range of motion) of the lips, jaw, tongue, and velum.   

Hearing Screening

A hearing screening is conducted during the comprehensive speech sound assessment, if one was not completed during the screening.

Hearing screening typically includes

  • otoscopic inspection of the ear canal and tympanic membrane;
  • pure-tone audiometry; and
  • immittance testing to assess middle ear function.

Speech Sound Assessment

The speech sound assessment uses both standardized assessment instruments and other sampling procedures to evaluate production in single words and connected speech.

Single-word testing provides identifiable units of production and allows most consonants in the language to be elicited in a number of phonetic contexts; however, it may or may not accurately reflect production of the same sounds in connected speech.

Connected speech sampling provides information about production of sounds in connected speech using a variety of talking tasks (e.g., storytelling or retelling, describing pictures, normal conversation about a topic of interest) and with a variety of communication partners (e.g., peers, siblings, parents, and clinician).

Assessment of speech includes evaluation of the following:

  • Accurate productions
    • sounds in various word positions (e.g., initial, within word, and final word position) and in different phonetic contexts;
    • sound combinations such as vowel combinations, consonant clusters, and blends; and
    • syllable shapes—simple CV to complex CCVCC.
  • Speech sound errors
    • consistent sound errors;
    • error types (e.g., deletions, omissions, substitutions, distortions, additions); and
    • error distribution (e.g., position of sound in word).
  • Error patterns (i.e., phonological patterns)—systematic sound changes or simplifications that affect a class of sounds (e.g., fricatives), sound combinations (e.g., consonant clusters), or syllable structures (e.g., complex syllables or multisyllabic words).

See Age of Acquisition of English Consonants (Roth & Worthington, 2018) and ASHA's resource on selected phonological processes (patterns). See also McLeod and Crowe (2018) for a cross-linguistic review of consonant acquisition.

Severity Assessment

Severity is a qualitative judgment made by the clinician indicating the impact of the child's speech sound disorder on functional communication. It is typically defined along a continuum from mild to severe or profound. There is no clear consensus regarding the best way to determine severity of a speech sound disorder—rating scales and quantitative measures have been used.

A numerical scale or continuum of disability is often used because it is time-efficient. Prezas and Hodson (2010) use a continuum of severity from mild (omissions are rare; few substitutions) to profound (extensive omissions and many substitutions; extremely limited phonemic and phonotactic repertoires). Distortions and assimilations occur in varying degrees at all levels of the continuum.

A quantitative approach (Shriberg & Kwiatkowski, 1982a, 1982b) uses the percentage of consonants correct (PCC) to determine severity on a continuum from mild to severe.

To determine PCC, collect and phonetically transcribe a speech sample. Then count the total number of consonants in the sample and the total number of correct consonants. Use the following formula:

PCC = (correct consonants/total consonants) × 100

A PCC of 85–100 is considered mild, whereas a PCC of less than 50 is considered severe. This approach has been modified to include a total of 10 such indices, including percent vowels correct (PVC; Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997).

Intelligibility Assessment

Intelligibility is a perceptual judgment that is based on how much of the child's spontaneous speech the listener understands. Intelligibility can vary along a continuum ranging from intelligible (message is completely understood) to unintelligible (message is not understood; Bernthal et al., 2017). Intelligibility is frequently used when judging the severity of the child's speech problem (Kent, Miolo, & Bloedel, 1994; Shriberg & Kwiatkowski, 1982b) and can be used to determine the need for intervention.

Intelligibility can vary depending on a number of factors, including

  • the number, type, and frequency of speech sound errors (when present);
  • the speaker's rate, inflection, stress patterns, pauses, voice quality, loudness, and fluency;
  • linguistic factors (e.g., word choice and grammar);
  • complexity of utterance (e.g., single words vs. conversational or connected speech);
  • the listener's familiarity with the speaker's speech pattern;
  • communication environment (e.g., familiar vs. unfamiliar communication partners, one-on-one vs. group conversation);
  • communication cues for listener (e.g., nonverbal cues from the speaker, including gestures and facial expressions); and
  • signal-to-noise ratio (i.e., amount of background noise).

Rating scales and other estimates that are based on perceptual judgments are commonly used to assess intelligibility. For example, rating scales sometimes use numerical ratings like 1 for totally intelligible and 10 for unintelligible, or they use descriptors like not at all, seldom, sometimes, most of the time, or always to indicated how well speech is understood (Ertmer, 2010).

A number of quantitative measures also have been proposed, including calculating the percentage of words understood in conversational speech (e.g., Flipsen, 2006; Shriberg & Kwiatkowski, 1980). See also Kent et al. (1994) for a comprehensive review of procedures for assessing intelligibility.

Coplan and Gleason (1988) developed a standardized intelligibility screener using parent estimates of how intelligible their child sounded to others. On the basis of the data, expected intelligibility cutoff values for typically developing children were as follows:

22 months—50%

37 months—75%

47 months—100%

See the Resources section for resources related to assessing intelligibility and life participation in monolingual children who speak English and in monolingual children who speak languages other than English.

Stimulability Testing

Stimulability is the child's ability to accurately imitate a misarticulated sound when the clinician provides a model. There are few standardized procedures for testing stimulability (Glaspey & Stoel-Gammon, 2007; Powell & Miccio, 1996), although some test batteries include stimulability subtests.

Stimulability testing helps determine

  • how well the child imitates the sound in one or more contexts (e.g., isolation, syllable, word, phrase);
  • the level of cueing necessary to achieve the best production (e.g., auditory model; auditory and visual model; auditory, visual, and verbal model; tactile cues);
  • whether the sound is likely to be acquired without intervention; and 
  • which targets are appropriate for therapy (Tyler & Tolbert, 2002).

Speech Perception Testing

Speech perception is the ability to perceive differences between speech sounds. In children with speech sound disorders, speech perception is the child's ability to perceive the difference between the standard production of a sound and his or her own error production—or to perceive the contrast between two phonetically similar sounds (e.g., r/w, s/sh, f/th).

Speech perception abilities can be tested using the following paradigms:  

  • Auditory Discrimination—syllable pairs containing a single phoneme contrast are presented, and the child is instructed to say "same" if the paired items sound the same and "different" if they sound different.
  • Picture Identification—the child is shown two to four pictures representing words with minimal phonetic differences. The clinician says one of these words, and the child is asked to point to the correct picture.
  • Pronunciation Accuracy/Inaccuracy
    • Speech production–perception task—using sounds that the child is suspected of having difficulty perceiving, picture targets containing these sounds are used as visual cues. The child is asked to judge whether the speaker says the item correctly (e.g., picture of a ship is shown; speaker says, "ship" or "sip"; Locke, 1980).
    • Mispronunciation detection task—using computer-presented picture stimuli and recorded stimulus names (either correct or with a single phoneme error), the child is asked to detect mispronunciations by pointing to a green tick for "correct" or a red cross for "incorrect" (McNeill & Hesketh, 2010).
    • Lexical decision/judgment task—using target pictures and single-word recordings, this task assesses the child's ability to identify words that are pronounced correctly or incorrectly. A picture of the target word (e.g., "lake") is shown, along with a recorded word—either "lake" or a word with a contrasting phoneme (e.g., "wake"). The child points to the picture of the target word if it was pronounced correctly or to an "X" if it was pronounced incorrectly (Rvachew, Nowak, & Cloutier, 2004).
Considerations For Assessing Young Children and/or Children Who Are Reluctant or Have Less Intelligible Speech

Young children might not be able to follow directions for standardized tests, might have limited expressive vocabulary, and might produce words that are unintelligible. Other children, regardless of age, may produce less intelligible speech or be reluctant to speak in an assessment setting.

Strategies for collecting an adequate speech sample with these populations include

  • obtaining a speech sample during the assessment session using play activities;
  • using pictures or toys to elicit a range of consonant sounds;
  • involving parents/caregivers in the session to encourage talking;
  • asking parents/caregivers to supplement data from the assessment session by recording the child's speech at home during spontaneous conversation; and
  • asking parents/caregivers to keep a log of the child's intended words and how these words are pronounced.

Sometimes, the speech sound disorder is so severe that the child's intended message cannot be understood. However, even when a child's speech is unintelligible, it is usually possible to obtain information about his or her speech sound production.

For example:

  • A single-word articulation test provides opportunities for production of identifiable units of sound, and these productions can usually be transcribed.
  • It may be possible to understand and transcribe a spontaneous speech sample by (a) using a structured situation to provide context when obtaining the sample and (b) annotating the recorded sample by repeating the child's utterances, when possible, to facilitate later transcription.
Considerations For Assessing Bilingual/Multilingual Populations

Assessment of a bilingual individual requires an understanding of both linguistic systems because the sound system of one language can influence the sound system of another language. The assessment process must identify whether differences are truly related to a speech sound disorder or are normal variations of speech caused by the first language.

When assessing a bilingual or multilingual individual, clinicians typically

  • gather information, including
    • language history and language use to determine which language(s) should be assessed,
    • phonemic inventory, phonological structure, and syllable structure of the non-English language, and
    • dialect of the individual;
  • assess phonological skills in both languages in single words as well as in connected speech;
  • account for dialectal differences, when present; and
  • identify and assess the child's
    • common substitution patterns (those seen in typically developing children),
    • uncommon substitution patterns (those often seen in individuals with a speech sound disorder), and
    • cross-linguistic effects (the phonological system of one’s native language influencing the production of sounds in English, resulting in an accent—that is, phonetic traits from a person’s original language (L1) that are carried over to a second language (L2; Fabiano-Smith & Goldstein, 2010).

See phonemic inventories and cultural and linguistic information across languages and ASHA's Practice Portal page on Bilingual Service Delivery. See the Resources section for information related to assessing intelligibility and life participation in monolingual children who speak English and in monolingual children who speak languages other than English.

Phonological Processing Assessment

Phonological processing is the use of the sounds of one's language (i.e., phonemes) to process spoken and written language (Wagner & Torgesen, 1987). The broad category of phonological processing includes phonological awareness, phonological working memory, and phonological retrieval.

All three components of phonological processing (see definitions below) are important for speech production and for the development of spoken and written language skills. Therefore, it is important to assess phonological processing skills and to monitor the spoken and written language development of children with phonological processing difficulties.

  • Phonological Awareness is the awareness of the sound structure of a language and the ability to consciously analyze and manipulate this structure via a range of tasks, such as speech sound segmentation and blending at the word, onset-rime, syllable, and phonemic levels.
  • Phonological Working Memory involves storing phoneme information in a temporary, short-term memory store (Wagner & Torgesen, 1987). This phonemic information is then readily available for manipulation during phonological awareness tasks. Nonword repetition (e.g., repeat "/pæg/") is one example of a phonological working memory task.
  • Phonological Retrieval is the ability to retrieve phonological information from long-term memory. It is typically assessed using rapid naming tasks (e.g., rapid naming of objects, colors, letters, or numbers). This ability to retrieve the phonological information of one's language is integral to phonological awareness.

Language Assessments

Language testing is included in a comprehensive speech sound assessment because of the high incidence of co-occurring language problems in children with speech sound disorders (Shriberg & Austin, 1998).

Spoken Language Assessment (Listening and Speaking)

Typically, the assessment of spoken language begins with a screening of expressive and receptive skills; a full battery is performed if indicated by screening results. See ASHA's Practice Portal page on Spoken Language Disorders for more details.

Written Language Assessment (Reading and Writing)

Difficulties with the speech processing system (e.g., listening, discriminating speech sounds, remembering speech sounds, producing speech sounds) can lead to speech production and phonological awareness difficulties. These difficulties can have a negative impact on the development of reading and writing skills (Anthony et al., 2011; Catts, McIlraith, Bridges, & Nielsen, 2017; Leitão & Fletcher, 2004; Lewis et al., 2011).

For typically developing children, speech production and phonological awareness develop in a mutually supportive way (Carroll, Snowling, Stevenson, & Hulme, 2003; National Institute for Literacy, 2009). As children playfully engage in sound play, they eventually learn to segment words into separate sounds and to "map" sounds onto printed letters.

The understanding that sounds are represented by symbolic code (e.g., letters and letter combinations) is essential for reading and spelling. When reading, children have to be able to segment a written word into individual sounds, based on their knowledge of the code and then blend those sounds together to form a word. When spelling, children have to be able to segment a spoken word into individual sounds and then choose the correct code to represent these sounds (National Institute of Child Health and Human Development, 2000; Pascoe, Stackhouse, & Wells, 2006).

Components of the written language assessment include the following, depending on the child's age and expected stage of written language development:

  • Print Awareness—recognizing that books have a front and back, recognizing that the direction of words is from left to right, and recognizing where words on the page start and stop.
  • Alphabet Knowledge—including naming/printing alphabet letters from A to Z.
  • Sound–Symbol Correspondence—knowing that letters have sounds and knowing the sounds for corresponding letters and letter combinations.
  • Reading Decoding—using sound–symbol knowledge to segment and blend sounds in grade-level words.
  • Spelling—using sound–symbol knowledge to spell grade-level words.
  • Reading Fluency—reading smoothly without frequent or significant pausing.
  • Reading Comprehension—understanding grade-level text, including the ability to make inferences.  

See ASHA's Practice Portal page on Written Language Disorders for more details.

Content Disclaimer: The Practice Portal, ASHA policy documents, and guidelines contain information for use in all settings; however, members must consider all applicable local, state and federal requirements when applying the information in their specific work setting.