Oct 3, 2026·Special Population & Related Conditions
How are bilingual children assessed? Telling a language difference from a disability
A sound bilingual assessment tests a child in every language they use, weighs language exposure, and avoids reading a language difference as a disability.
Dr. Russell T. WarneChief Scientist
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Bilingual children are assessed in every language they use, by an examiner who speaks those languages or works with a trained interpreter, using a mix of standardized tests interpreted with caution, language samples, a detailed history of language exposure, and methods such as dynamic assessment that measure how quickly a child learns. The central task is to separate a normal language difference from a genuine disability. In the United States, federal special education law requires the evaluation to be given in the child's native language unless that is clearly not feasible.
This article covers what the law requires, why a translated test is not equivalent to the original, which tools hold up better, where nonverbal tests and interpreters fit, and what the research shows about English learners being both over- and under-identified for special education.
What the law requires: native language, "unless clearly not feasible"
The governing rule for a public school evaluation is 34 CFR 300.304(c)(1)(ii). Assessments must be "provided and administered in the child's native language or other mode of communication and in the form most likely to yield accurate information on what the child knows and can do academically, developmentally, and functionally, unless it is clearly not feasible to so provide or administer."
Two related definitions sharpen the rule. Under 34 CFR 300.29, "native language" in direct contact with a child, including evaluation, means "the language normally used by the child in the home or learning environment," which is not always the parents' language. And 34 CFR 300.306(b) bars a district from finding a child eligible for special education if the "determinant factor" is limited English proficiency. A child who struggles in English class because they arrived from Guatemala eight months ago has not shown a disability.
The same regulation also requires assessments to be "administered in accordance with any instructions provided by the producer." That creates a real tension. Most published tests were standardized in one language, so giving them any other way departs from the producer's instructions. Evaluators handle the conflict by choosing instruments that exist in the child's language and by reporting plainly when a score cannot be interpreted against norms. A full psychoeducational evaluation for a bilingual child should state which language each measure was given in and why.
Language difference or disorder?
A "language difference" is the normal pattern of a child acquiring two languages: smaller vocabulary in each language than a monolingual peer, grammatical features borrowed from one language into the other, and uneven skills that depend on where each language is used. A language disorder is an underlying impairment in learning language at all.
The key diagnostic principle, as the American Speech-Language-Hearing Association puts it, is that "signs of a communication disorder are seen across all the languages that a multilingual person uses." Kohnert's (2010) review makes the same point: "For bilingual children with PLI, the underlying impairment manifests in both languages." A child with weak English and strong, age-appropriate Spanish has a difference. A child who is behind in both, relative to bilingual peers with similar exposure, may have a disorder.
Vocabulary shows why single-language testing misleads. In an analysis of 1,738 children aged 3 to 10, Bialystok, Luk, Peets, and Yang (2010) found that bilingual children consistently scored lower than monolinguals on an English receptive vocabulary test, with the gap concentrated in words tied to home life rather than school. Earlier, Pearson, Fernández, and Oller (1993) showed that when bilingual toddlers' words in both languages were counted together, there was no statistical basis for concluding that they developed vocabulary more slowly. Their conclusion was that bilingual norms should be built on performance "in two languages together."
Choosing the tools: translations, dynamic assessment, and norms
Why a translated test is not the same test
Translating a test item by item produces a different test. Words that are common in one language can be rare in another, a grammatical form tested in English may not exist in Spanish, and pictures may depict objects children in another culture have never seen. Each of those shifts changes item difficulty, so the original norms no longer apply.
The International Test Commission's Guidelines for Translating and Adapting Tests (2017) require developers to "provide relevant statistical evidence about the construct equivalence, method equivalence, and item equivalence" of an adapted version and to "provide evidence supporting the norms, reliability and validity of the adapted version of the test in the intended populations." ASHA is blunter for practitioners: "It is not appropriate to translate standardized assessments without proper validation studies to reach a standard score." An examiner translating on the fly, or an interpreter reading items aloud, can gather useful observations, but the resulting numbers should not be reported as standard scores.
What holds up better
No single instrument solves the problem. Kohnert noted that "there are currently no published tests that can be used to independently identify PLI in any group of bilingual learners." Evaluators therefore combine sources:
• Testing in both languages: Measures given in each language, interpreted together, show the child's total ability rather than half of it.
• Language exposure history: Parent interviews about when each language was introduced, who speaks what at home, and years of schooling in each language are essential for judging what performance to expect.
• Language samples: Conversation or story retelling in each language, analyzed for grammar and complexity, avoids many of the vocabulary biases of picture tests.
• Dynamic assessment: A test-teach-retest format that measures how readily a child learns a new skill with brief instruction. In one study of Spanish-English bilingual children, Peña, Gillam, and Bedore (2014) found that dynamic assessment of narrative skill, conducted in English, classified children with and without language impairment with 80.6% to 97.2% accuracy.
• Bilingual norms: Where they exist, norms drawn from children with similar bilingual backgrounds are preferable to monolingual norms in either language, though such instruments remain few.
Nonverbal tests and interpreters: useful, with limits
When the question involves intellectual ability, evaluators often turn to nonverbal batteries such as the Universal Nonverbal Intelligence Test or the Wechsler Nonverbal Scale of Ability, which minimize spoken language in both instructions and responses. They are a reasonable choice, but they do not erase group differences. In a study of 1,198 elementary students, roughly 40% of them English learners, Lohman, Korb, and Lakin (2008) found that English learners scored 0.5 to 0.67 standard deviations lower than non-English learners on three nonverbal tests, that national norms on two of the tests were flawed, and that none of the nonverbal tests predicted achievement for English learners very well. A nonverbal score also measures only part of intelligence, leaving verbal reasoning unassessed.
Interpreters fill a necessary role, but ASHA recommends working with trained interpreters rather than family members, notes that untrained interpreters "may unintentionally misrepresent a meaning," and warns that minors may lack the emotional maturity for the role. Good practice follows a briefing, interaction, and debriefing sequence, so the interpreter knows in advance which items must be rendered word for word and can report afterward on anything that did not translate cleanly.
Overidentification and underidentification of English learners
The research shows errors in both directions, and which one dominates depends on grade, language proficiency, and how the data are analyzed.
• Overidentification: Sullivan (2011), analyzing statewide data from a southwestern state, found that English learners became increasingly likely over time to be identified with learning disabilities or intellectual disability relative to White peers. Artiles, Rueda, Salazar, and Higareda (2005) found in California urban districts that students with limited proficiency in both their native language and English, particularly in secondary grades, were the most affected.
• Underidentification: Using national longitudinal data with extensive controls, Morgan and colleagues (2015) found that language-minority children were less likely than otherwise similar English-speaking White children to be identified with learning disabilities or speech or language impairments.
• Both, by grade: Samson and Lesaux (2009) found that language-minority learners were underrepresented in special education in kindergarten and first grade but overrepresented by third grade across all disability categories.
One plausible reading of the pattern is that schools often wait too long while a child is "still learning English," then over-attribute later difficulties to disability. Careful assessment in both languages is the main defense against both mistakes.
Frequently asked questions
Should a bilingual child be tested in English or their home language?
Ideally both. Federal regulations require testing in the child's native language unless clearly not feasible, and testing in every language the child uses is the most reliable way to distinguish a language difference from a disorder.
Can a bilingual child be diagnosed with a language disorder?
Yes. Bilingualism does not cause language disorders, but a true disorder will show up in both languages, so the diagnosis rests on weakness in each language relative to bilingual peers with similar exposure.
Is it acceptable to use a translated version of an English test?
Only if the translated version has its own validation evidence and norms. An informal translation can provide observations, but its scores should not be reported as standard scores.
Are nonverbal IQ tests fair for English learners?
They reduce the language load, which helps, but research shows English learners still score lower on average and that some nonverbal tests have weak norms. They are best used as one part of a broader evaluation.
Can a school refuse to evaluate a child because they are an English learner?
Being an English learner is not a reason to delay an evaluation when a disability is suspected. The law forbids identifying a child as disabled because of limited English proficiency alone, but it does not exempt English learners from evaluation.
The takeaway
Assessing a bilingual child well means treating both languages as part of the child's ability. Testing in one language, especially with a translated test or monolingual norms, tends to understate what a bilingual child knows. Dynamic assessment, language samples, a careful exposure history, and nonverbal measures used with their limits in mind make the picture sharper, and the research on over- and under-identification shows why the extra effort matters. Readers curious about standardized measurement of reasoning can take the RIOT IQ test, which reports scores against a defined norm group with their margin of error.
References
1. U.S. Department of Education. (2006). Evaluation procedures, 34 CFR 300.304. law.cornell.edu
2. U.S. Department of Education. (2006). Native language, 34 CFR 300.29. law.cornell.edu
3. U.S. Department of Education. (2006). Determination of eligibility, 34 CFR 300.306. law.cornell.edu
4. American Speech-Language-Hearing Association. (n.d.). Multilingual service delivery in audiology and speech-language pathology [Practice Portal]. asha.org
5. Kohnert, K. (2010). Bilingual children with primary language impairment: Issues, evidence and implications for clinical actions. Journal of Communication Disorders, 43(6), 456-473. doi.org
6. Bialystok, E., Luk, G., Peets, K. F., & Yang, S. (2010). Receptive vocabulary differences in monolingual and bilingual children. Bilingualism: Language and Cognition, 13(4), 525-531. doi.org
7. Pearson, B. Z., Fernández, S. C., & Oller, D. K. (1993). Lexical development in bilingual infants and toddlers: Comparison to monolingual norms. Language Learning, 43(1), 93-120. doi.org
8. International Test Commission. (2017). The ITC guidelines for translating and adapting tests (2nd ed.). intestcom.org
9. Peña, E. D., Gillam, R. B., & Bedore, L. M. (2014). Dynamic assessment of narrative ability in English accurately identifies language impairment in English language learners. Journal of Speech, Language, and Hearing Research, 57(6), 2208-2220. doi.org
10. Lohman, D. F., Korb, K. A., & Lakin, J. M. (2008). Identifying academically gifted English-language learners using nonverbal tests: A comparison of the Raven, NNAT, and CogAT. Gifted Child Quarterly, 52(4), 275-296. doi.org
11. American Speech-Language-Hearing Association. (n.d.). Collaborating with interpreters, transliterators, and translators [Practice Portal]. asha.org
12. Sullivan, A. L. (2011). Disproportionality in special education identification and placement of English language learners. Exceptional Children, 77(3), 317-334. doi.org
13. Artiles, A. J., Rueda, R., Salazar, J. J., & Higareda, I. (2005). Within-group diversity in minority disproportionate representation: English language learners in urban school districts. Exceptional Children, 71(3), 283-300. doi.org
14. Morgan, P. L., Farkas, G., Hillemeier, M. M., Mattison, R., Maczuga, S., Li, H., & Cook, M. (2015). Minorities are disproportionately underrepresented in special education: Longitudinal evidence across five disability conditions. Educational Researcher, 44(5), 278-292. doi.org
15. Samson, J. F., & Lesaux, N. K. (2009). Language-minority learners in special education: Rates and predictors of identification for services. Journal of Learning Disabilities, 42(2), 148-162. doi.org
Hero image: Paul Breaux Middle School sign, Lafayette, Louisiana, by Christophe Landry, licensed CC BY-SA 3.0 (creativecommons.org/licenses/by-sa/3.0). Via Wikimedia Commons.
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