Comprehensive Guide to CASL‑2 Subtests for Clinicians

Updated on: July 25, 2025

Introduction

The Comprehensive Assessment of Spoken Language, Second Edition (CASL‑2), is a norm-referenced tool designed to evaluate oral language skills across a wide age range. Grounded in Integrated Language Theory, it assesses individuals from early childhood through young adulthood and is widely used by speech-language pathologists, psychologists, and educational professionals to identify language strengths and weaknesses.

This guide offers clinicians a detailed breakdown of each CASL‑2 subtest, interpretations of scoring, visuals to assist in understanding test profiles, and tips for applying results in real-world clinical scenarios. It’s crafted to enhance clarity and application of the tool for diagnosis and therapy planning.

Structural Framework of CASL‑2

CASL‑2 categorizes its fourteen subtests into four major domains:

• Lexical/Semantic: Focuses on vocabulary knowledge, word meanings, and semantic relationships.
• Syntactic: Assesses grammatical structures and sentence construction.
• Supralinguistic: Evaluates nonliteral, inferential, and abstract aspects of language.
• Pragmatic: Measures the appropriate use of language in social contexts.

Based on combinations of these subtests, CASL‑2 provides six index scores that summarize language abilities:

• General Language Ability Index (GLAI): A broad measure of overall spoken language competence.
• Receptive Language Index (RLI): Reflects understanding and interpretation of language.
• Expressive Language Index (ELI): Evaluates language production abilities.
• Lexical/Semantic Index (LSI)
• Syntactic Index (SI)
• Supralinguistic Index (SPI)

These indices allow for a holistic understanding of an individual’s language profile.

CASL‑2 Subtests: Descriptions and Interpretations

Lexical/Semantic Domain

Receptive Vocabulary
This subtest measures a person’s ability to understand spoken words and identify corresponding images or concepts. It reflects the foundational knowledge of everyday vocabulary and is particularly useful for younger children.

Antonyms
The goal here is to assess whether an individual can identify or produce words with opposite meanings. This taps into vocabulary depth and semantic organization.

Synonyms
This evaluates the ability to understand and select words with similar meanings. Strong performance indicates a well-developed vocabulary and semantic awareness.

Expressive Vocabulary
In this task, clients are asked to name objects, actions, or provide words that complete sentences. It measures the ease and accuracy with which they can retrieve vocabulary for expressive purposes.

Idiomatic Language
Clients interpret figurative expressions or complete idiomatic phrases. This subtest requires both language proficiency and cultural familiarity and is often challenging for individuals with literal interpretation styles.

Syntactic Domain

Sentence Expression
Individuals are shown images and asked to formulate complete and grammatically correct sentences that describe them. This evaluates their ability to construct syntactically sound sentences.

Grammatical Morphemes
This subtest examines the use of function words and inflections like plurals, verb tenses, and articles. It is key for understanding developmental grammatical competence.

Sentence Comprehension
Clients are given sentences and asked to interpret or match them with pictures. This assesses their understanding of complex sentence structures, including passives and embedded clauses.

Grammaticality Judgment
Participants listen to or read sentences and judge whether they are grammatically correct. They may be asked to explain or correct incorrect ones, testing metalinguistic awareness.

Supralinguistic Domain

Nonliteral Language
This measures the ability to interpret sarcasm, metaphors, or indirect language. It reflects social cognition and is crucial for advanced communication and understanding humor or emotional nuance.

Meaning from Context
Individuals infer the meanings of unfamiliar words based on sentence or paragraph context. This is essential for vocabulary growth, particularly in reading and academic settings.

Inference
Participants must read between the lines or draw conclusions based on given information. This ability is tied closely to critical thinking and language comprehension.

Double Meaning
Clients interpret sentences or phrases that have more than one meaning. Success here demonstrates flexibility in language processing and metalinguistic skills.

Pragmatic Domain

Pragmatic Language (Judgment)
This evaluates the client’s understanding of appropriate language use in different social contexts. It includes interpreting conversational cues, making polite requests, or adjusting speech for different audiences.

Administration and Scoring Overview

CASL‑2 is designed for individuals aged three to twenty-one. It is modular, meaning clinicians can select subtests based on referral concerns, age, and time availability.

Administration Time
Each subtest typically takes between five to ten minutes. Administering the core four or five subtests to calculate the General Language Ability Index usually takes around forty-five minutes.

Scoring and Norms
CASL‑2 subtests yield standard scores with a mean of one hundred and a standard deviation of fifteen. Percentile ranks and descriptive categories help contextualize these scores.

Standard score interpretation:

Index scores are derived by combining multiple subtest scores. Clinicians should be cautious when interpreting discrepancies between subtests, especially if one score is significantly higher or lower than others in the same domain.

Profile Visualization and Analysis

Here’s an example of how subtest scores can be presented for interpretation:

In this case, while all scores fall within the average range, the discrepancy between the highest and lowest scores may still warrant targeted attention, especially if the individual’s real-world language performance is uneven.

Clinicians should examine whether gaps exceed critical values provided in the CASL‑2 manual. Differences of more than ten standard points between subtests can be considered statistically and clinically significant depending on the standard error.

Age-Based Considerations

Norms are age-stratified, especially in early childhood. Subtests are not all applicable to all ages. For instance, complex tasks like idiomatic or double-meaning subtests may not be administered to children under age nine.

Test results should always be interpreted in the context of age expectations and developmental milestones.

Using CASL‑2 in Clinical Settings

Comprehensive Diagnosis
CASL‑2 can help diagnose a wide variety of language disorders, including:

• Expressive language disorder
• Receptive language disorder
• Mixed receptive-expressive disorder
• Pragmatic language impairment
• Specific language impairment (SLI)
• Language delay due to neurodevelopmental conditions

Therapy Planning
Use subtest results to design individualized therapy goals. For example:

• Low scores in Expressive Vocabulary suggest targeting word retrieval and naming exercises.
• Weak performance on Nonliteral Language may indicate a need for figurative language and social language intervention.
• Discrepancies between expressive and receptive scores guide which modality needs more emphasis.

Progress Monitoring
CASL‑2 has high test-retest reliability, making it suitable for tracking language growth over time. Reassessment every six to twelve months can help measure therapy outcomes and refine goals.

Social Language Assessment
For children with suspected autism or pragmatic language disorder, the Pragmatic Language subtest, along with Supralinguistic subtests, can reveal difficulties in social communication, inference, and conversational understanding.

Case Study Example

Client Profile
Aiden, aged seven years and seven months, was referred for evaluation due to concerns about classroom participation and vocabulary use.

CASL‑2 Results

Interpretation
Aiden shows solid receptive vocabulary and strong expressive word recall, but has difficulty identifying antonyms and synonyms. His grammar use, particularly in morphosyntax, is also an area of concern. These results suggest a semantic processing weakness and difficulties with grammar rules. Intervention should focus on semantic relationships and grammatical accuracy.

Customizing the Battery

Depending on referral questions, clinicians can tailor subtests:

• For vocabulary concerns: Receptive Vocabulary, Antonyms, Synonyms, Expressive Vocabulary
• For syntax issues: Sentence Comprehension, Grammatical Morphemes, Sentence Expression
• For social communication: Pragmatic Judgment, Inference, Nonliteral Language
• For academic underperformance: Meaning from Context, Double Meaning

Best Practices for Interpretation

• Look at intra-index variability. Differences within the same domain (e.g., high expressive, low receptive) can reveal specific learning styles or deficits.
• Always integrate test data with classroom observations, teacher reports, and dynamic assessments.
• Use descriptive language in reports: avoid labeling a child as “low” based on one subtest. Instead, describe the nature of the difficulty and how it may impact communication.

Limitations and Considerations

• Cultural and linguistic backgrounds may affect results. CASL‑2 includes alternative norms for African American English speakers but does not provide full bilingual assessment tools.
• Some children may struggle with the test structure or motivation, particularly those with attention deficits or autism spectrum disorder.
• Results must be interpreted with caution in cases of co-occurring conditions like ADHD, learning disabilities, or emotional disturbances.

Summary and Recommendations

CASL‑2 offers clinicians a flexible and comprehensive tool to assess the complexities of spoken language. By selecting age-appropriate subtests and interpreting both individual and composite scores, clinicians can:

• Accurately identify language deficits
• Customize therapy plans to the child’s strengths and needs
• Monitor language development with reliable measures

For best results, combine CASL‑2 findings with real-world observations, teacher and parent interviews, and functional assessments. Use the test not only as a diagnostic tool but also as a map to guide the journey of intervention and support.

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