What is the CASL-2? The Comprehensive Assessment of Spoken Language explained

The CASL-2 (Comprehensive Assessment of Spoken Language, Second Edition) is an individually administered oral language battery for children and young adults ages 3 to 21, written by Elizabeth Carrow-Woolfolk, PhD, and published by WPS in 2017. It measures spoken language through 14 stand-alone tests organized into four categories: lexical/semantic, syntactic, supralinguistic, and pragmatic language. No reading or writing is required at any point. The examiner reads every item aloud, and the examinee answers by speaking or pointing. This article explains what the CASL-2 measures, how its tests and scores work, how it relates to the same author's OWLS-II, and how a spoken language battery differs from an IQ test.

According to WPS, the CASL-2 measures "the oral language processing skills of comprehension and expression" across four structural categories. Each category targets a different layer of spoken language.

• Lexical/semantic: knowledge and use of words and word combinations. This ranges from pointing to a named picture at age 3 to producing synonyms, antonyms, and idioms in adolescence.

• Syntactic: knowledge and use of grammar, including grammatical word endings, sentence structure, and the ability to judge whether a sentence is grammatically correct.

• Supralinguistic: the publisher defines this as knowledge and use of language "in which meaning is not directly available from the surface lexical and syntactic information." In plain terms, this covers inference, nonliteral language, and figuring out what words mean from context.

• Pragmatic language: knowledge of what language is appropriate in different situations and the ability to adjust language to the social context, such as knowing what to say when answering a phone or asking for help.

These categories map closely onto the language domains that the American Speech-Language-Hearing Association describes in its guidance on spoken language disorders, which lists morphology, syntax, semantics, and pragmatics among the areas a comprehensive language evaluation should address. The CASL-2 does not assess phonology (speech sounds), so examiners pair it with an articulation measure when speech production is also a concern.

The CASL-2 contains 14 stand-alone tests, each taking about 5 to 10 minutes. Because every test is independently normed, an examiner can give a single test, a category, or a full battery. Per the publisher's test table, the tests break down by category as follows.

• Lexical/semantic tests (five): Receptive Vocabulary (ages 3 to 21), Antonyms (5 to 21), Synonyms (5 to 21), Expressive Vocabulary (3 to 21), and Idiomatic Language (9 to 21).

• Syntactic tests (four): Sentence Expression (3 to 21), Grammatical Morphemes (3 to 21), Sentence Comprehension (3 to 21), and Grammaticality Judgment (5 to 21).

• Supralinguistic tests (four): Nonliteral Language (7 to 21), Meaning From Context (7 to 21), Inference (3 to 21), and Double Meaning (9 to 21).

• Pragmatic test (one): Pragmatic Language (3 to 21), which asks the examinee to say what would be appropriate in everyday social situations.

WPS notes that the Pragmatic Language Test is the only performance-based test of pragmatic language for children under age 6, which makes it a common choice when evaluating young children for autism spectrum disorder or "social (pragmatic) communication disorder," a diagnosis involving persistent difficulty with the social use of language. Compared with the original CASL published in 1999, the second edition dropped the Paragraph Comprehension test, extended most tests to younger ages, and renormed everything.

Each CASL-2 test yields a standard score on the familiar mean-100 scale with a "standard deviation" (a measure of how spread out scores are) of 15 points, along with percentile ranks, descriptive ranges, confidence intervals, test-age equivalents, and grade equivalents. Test scores combine into up to six index scores, tailored to the examinee's age.

• General Language Ability Index (GLAI): the overall spoken language score, comparable in role to a full scale score on a cognitive battery. WPS reports that the GLAI can be obtained by administering just four to five tests, taking about 45 minutes.

• Receptive and Expressive Language Indexes: processing-based scores that separate how well a person understands spoken language from how well they produce it.

• Lexical/Semantic, Syntactic, and Supralinguistic Indexes: categorical scores that localize a weakness to vocabulary, grammar, or higher-level meaning.

The norms come from a stratified national sample of 2,394 individuals ages 3 to 21, matched to U.S. Census data for gender, ethnicity, region, and parent education. The publisher also reports a clinical validation sample of 271 individuals showing that the test differentiates typically developing examinees from groups with language disorders, hearing impairment, autism spectrum disorder, social (pragmatic) communication disorder, intellectual disability, learning disability, and developmental delay. Alternative scoring guidelines are provided so that dialect differences, such as features of African American English, are not miscounted as errors.

Administration is deliberately simple. The examiner works from one of three easels, reads each item aloud, and records the spoken or pointed response by hand on a record form. All tests share the same "basal" and "ceiling" rules (the starting and stopping points of a test): four consecutive correct responses establish the basal, and four consecutive errors end the test. A Preschool Form covers the 10 tests usable with children ages 3 to 6, while the Comprehensive Form covers all 14 tests across the full age range.

Because no reading or writing is involved, the CASL-2 isolates oral language from literacy. A child with dyslexia who struggles on written tests can still show intact spoken language here, and conversely, a low CASL-2 score cannot be blamed on reading problems. That purity of measurement is one of the main reasons speech-language pathologists reach for it. WPS classifies the CASL-2 as a qualification level C instrument, meaning it is sold to professionals with graduate training in assessment, typically SLPs, school psychologists, and related specialists.

The CASL-2 belongs to a family of instruments built on Carrow-Woolfolk's "Integrative Language Theory," a model of how meaning, language structure, and language use develop together. Her OWLS-II (Oral and Written Language Scales, Second Edition) covers the same ages but adds reading comprehension and written expression scales, so it surveys oral and written language broadly while the CASL-2 drills deeper into 14 spoken language skills. A third companion, the Oral Passage Understanding Scale (OPUS), measures listening comprehension of connected passages and was co-normed with the CASL-2.

The main competitor is Pearson's CELF-5 (Clinical Evaluation of Language Fundamentals, Fifth Edition), the most widely used school-age language battery. WPS reports comparative studies showing strong correlations between the CASL-2 and the CELF-5, OWLS-II, OPUS, and original CASL, while arguing the tests remain distinct enough to measure different aspects of spoken language. In practice, examiners often prefer the CASL-2 when they want its supralinguistic and pragmatic coverage, its extension down to age 3, or a battery that never requires reading.

WPS lists speech-language pathologists as the primary users, working in schools, clinics, hospitals, private practices, and intervention programs. Typical referral questions include eligibility for speech and language services, special education placement, identifying a language delay or disorder, tracking response to intervention, and measuring the language abilities of English learners.

The CASL-2 is a language test, though, and language ability is only part of cognitive ability. Oral language skill overlaps substantially with verbal reasoning, the ability to reason with words and word meanings, but a language battery does not measure fluid reasoning, spatial ability, working memory, or processing speed. A child can have a serious spoken language disorder alongside average or better nonverbal intelligence, and untangling the two usually requires both a language evaluation and a cognitive one.

For adults who want a broad, normed picture of cognitive ability rather than a clinical language workup, the RIOT IQ test (the Reasoning and Intelligence Online Test), developed by RIOT IQ with psychometrician Dr. Russell T. Warne, measures 15 subtests across six cognitive indices, including verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes and reports scores on the same mean-100, standard-deviation-15 scale the CASL-2 uses. It is designed for adults 18 and older and does not replace an individually administered diagnostic evaluation, but it is a rigorous way to see how your reasoning compares with other adults. You can take the RIOT IQ test at riotiq.com.

The CASL-2 is normed for ages 3 years, 0 months through 21 years, 11 months. Individual tests have narrower ranges; for example, Idiomatic Language and Double Meaning begin at age 9.

Each test takes about 5 to 10 minutes. The General Language Ability Index requires four to five tests and roughly 45 minutes. A fuller battery can run longer depending on how many tests the examiner selects.

No. Every item is presented orally by the examiner, and the examinee responds by speaking or pointing. This makes it useful for separating oral language ability from literacy problems.

No. It measures spoken language comprehension and expression, which overlaps with verbal ability but leaves out nonverbal reasoning, spatial ability, memory, and speed. Language scores and IQ scores answer different questions.

Both were written by Elizabeth Carrow-Woolfolk and cover ages 3 to 21. The OWLS-II surveys four broad scales spanning oral and written language, while the CASL-2 provides 14 spoken language tests for a more detailed oral profile.

WPS sells it at qualification level C, generally meaning professionals with graduate training in psychological or speech-language assessment, most often speech-language pathologists.

1. Western Psychological Services. (2017). (CASL-2) Comprehensive Assessment of Spoken Language, Second Edition [Product page]. wpspublish.com

2. Western Psychological Services. (n.d.). CASL-2 and OPUS tests [Test table]. mindresources.com

3. Stoelting Co. (n.d.). Comprehensive Assessment of Spoken Language, Second Edition (CASL-2) [Product page]. stoeltingco.com

4. TheraPlatform. (n.d.). CASL assessment [Blog post]. theraplatform.com

5. Western Psychological Services. (n.d.). (OWLS-II) Oral and Written Language Scales, Second Edition [Product page]. wpspublish.com

6. American Speech-Language-Hearing Association. (n.d.). Spoken language disorders [Practice Portal]. asha.org

Hero photo: Two wooden chairs facing each other across a small round table in a bright window corner, the kind of quiet one-on-one setting where an examiner administers the spoken-language items of the CASL-2. Photo by Shixart1985, CC BY 2.0, via Wikimedia Commons; cropped from the original.