Lexical Tasks


What are CLTs?


CLT are picture-choice and picture-naming tasks that assess the comprehension and production of nouns and verbs via four subtasks. Each of the four subtasks consists of 32 items. Typically CLT is used in studies of multilingual and monolingual children aged between 3 and 7 years. CLT is currently available in 38 languages and in the form of a mobile app for iPads and Android tablets.

Each language version of CLT was developed according to the same procedure and criteria. Therefore for cross-linguistic comparison, CLT is not translated but constructed for each language separately. The rules of CLT construction are based on words’ semantics, age of acquisition, and phonological and morphological complexity.

CLT are a part of the Language Impairment Testing in Multilingual Settings (LITMUS) battery and were originally developed in COST Action IS0804 (2010–2013) ‘Language Impairment in a Multilingual Society: Linguistic Patterns and the Road to Assessment’ ( 



Arabic (Lebanese)

Khoury Aouad Saliby, Kouba-Hreich & Messarra


Chan, Kan & Hamdani


Gavarró & Montes


Łuniewska & Smolík


van Wonderen, Blom, Boerma, van Dijk, Janssen, & Unsworth

English (American)

Haman, Miller, Wodniecka, Koegler & Łuniewska

English (British)

Haman, Łuniewska, Polisenka, Mieszkowska & Chiat

English (Malaysian)

Waey & Yap

English (South African)



Vaks, Vihman & Padrik




dos Santos & Prévost


Rinker & Gagarina


Tselekidou, Rizou & Gagarina


Armon-Lotem & Harel


Ehret & Marton




Southwood & Potgieter


Roch, Levorato & Tedeschi


Blažienė, Dabašinskienė & Łuniewska


Engel De Abreu, Gilles, Łuniewska & Haman


Yap, Razak, Treffers-Daller, Łuniewska & Haman


Gatt & Łuniewska




Simonsen, Hansen & Łuniewska



Polish (revised)

Haman, Łuniewska, Krysztofiak, Pomiechowska, Szewczyk & Wodniecka


Gagarina & Nennonen

Scottish Gaelic

Chondrogianni, Butcher & Cox

Serbian 1

Vuksanović & Bjekić

Serbian 2

Anđelković, Popović & Savić


Kapalková, Slančová, Łuniewska & Haman




Ringblom, Håkansson & Lindgren


Yılmaz-Çifteci, Tunçer, Ünal & Ege


Hamdani, Kan & Chan

Western Armenian

Gureghian, Abboud & Tuller

How CLTs are constructed?

Each CLT language version was developed according to the same set of criteria. The selection of target words in each language is based on two main measures of word difficulty: subjective age of acquisition of words and complexity index that takes into account the phonological and morphological properties of words. Additionally, while developing a CLT version we control for naming agreement of the pictures. When a CLT version is ready, it may be incorporated into the mobile app.

Detailed information

CLT have been developed in cooperation with over 40 institutions
the post-doc position (2020-2026) is funded within the Excellence Initiative – Research University (IDUB) programme by the Ministry of Science and Higher Education; We acknowledge previous and current financial support from: COST Action IS0804 (2010-2013); Polish Ministry of Science and Higher Education (2010-2015); National Science Center in Poland; The Kościuszko Foundation (2015), Visegrad Fund (2015-2016); Faculty of Psychology University of Warsaw (2013-2016, 2020-2024)
since 2010
dr Magdalena Łuniewska
prof. Ewa Haman
Magdalena Krysztofiak

1. Naming study

Aim: To prepare the list of candidate words in the language.

Description: Adult native speakers of the target language name the pictures selected from the set of over 500 CLT pictures. The pictures are freely available for research:

Result: The most widely shared names given to the pictures compose the list of candidate words used in the next steps. The target words are later selected from the names.

Publications: Polish norms for the picture base have been published by Wolna et al., 2023.

2. AoA study

Aim: To estimate words’ difficulty (based on the speakers’ intuitions).

Description: For each of the candidate words, native speakers of the target language answer the question: When did you learn the word ‘X’? The ratings provided by the native speakers are then averaged and used as a measure of words’ difficulty.

Result: The average rating for each word will be used as one of the difficulty measures.

Publications: The AoA ratings have been published in 32 languages: Łuniewska et al., 2016 and Łuniewska et al., 2019

3. Complexity assessment

Aim: To estimate words’ difficulty.

Description: A linguist who speaks the target language provides detailed information about the phonological and morphological characteristics of the words. The complexity index is calculated based on this information.

Result: The computed complexity index will be used as the second measure of words’ difficulty.

4. Construction

Aim: To construct the CLT.

Description: The target words for comprehension and production subtasks are selected on the basis of the words’ age of acquisition and complexity according to the cross-linguistic rules. The CLT should include early and later words of various complexity.

Result: A pilot version of CLT in the target language is ready for a pilot study!

5. Pilot study

Aim: To revise the pilot version of the CLT.

Description: At least 10 monolingual children (typically five-year-olds) are tested with the pilot version of CLT. The items that are poorly recognized or named by children are later revised.

Result: The final version of CLT is ready to be used in research!

6. App version

Aim: To prepare the mobile app version of the CLT.

Description: The recording of questions and batch files are incorporated into the Child Lexicon CLT app.

Result: The new language is added to the app available from the App Store and Google Play.

CLTs design and validation

Haman, E., Łuniewska, M., & Pomiechowska, B. (2015). Designing Cross-linguistic Lexical Tasks (CLTs) for bilingual preschool children. In S. Armon-Lotem, J. de Jong & N. Meir (Eds.). Methods for assessing multilingual children: disentangling bilingualism from Language Impairment. Bristol: Multilingual Matters.


Łuniewska, M., Haman, E., & Hansen, P. (2016). Is there a road to universal assessment of lexical knowledge in multilingual children? Cross-cultural aspects of Cross-linguistic Lexical Tasks. In H.-O. Enger, M. I. N. Knoph, K. E. Kristoffersen & M. Lind (Eds.), Helt fabelaktig! Festskrift til Hanne Gram Simonsen på 70-årsdagen: 147–165. Oslo, Norway: Novus Forlag.


Smolík, F., & Bytešníková, I. (2021). Validity of the SDDS: A 40-item vocabulary screening tool for 18- to 42-month olds in Czech. Journal of Communication Disorders93, 106146.

van Wonderen, E. V., & Unsworth, S. (2020). Testing the validity of the Cross-Linguistic Lexical Task as a measure of language proficiency in bilingual children. Journal of Child Language, 1–25.


Yap, N. T., Razak, R. A., Haman, E., Łuniewska, M., & Treffers-Daller, J. (2017). Construction of the Malay Cross-linguistic Lexical Task: A preliminary report. Language Studies Working Papers, 8, 47–61.


Yılmaz-Çifteci, N., &  Tuncer, A. M. (2022). Validity and Reliability of the Cross-Lingusitic Lexical Task Turkish: Preliminary StudyTürkiye Klinikleri Sağlık Bilimleri Dergisi, doi: 10.5336/healthsci.2021-87316

CLTs in monolingual and multilingual children

Abbot-Smith, K., Morawska-Patera, P., Łuniewska, M., Spruce, M., & Haman, E. (2018). Using parental questionnaires to investigate the heritage language proficiency of bilingual children. Child Language Teaching & Therapy, 34(2), 155-170.


Altman, C., Goldstein, T., & Armon-Lotem, S. (2017). Quantitative and qualitative differences in the lexical knowledge of monolingual and bilingual children on the LITMUS-CLT task. Clinical Linguistics & Phonetics, 31(11-12), 931-954.


Baumgartner, R. & Rinker, T. (2018). Mehrsprachigkeit am Übergang von Kita und Grundschule – Potenziale von Kindern und Fachkräften aufdecken und entfalten. In A. Blechschmidt & U. Schräpler (Eds.), Mehrsprachigkeit in Sprachtherapie und Unterricht, 129-145. Basel: Schwabe.


Bohnacker, U., Lindgren, J., & Öztekin, B. (2016). Turkish- and German-speaking bilingual 4-to-6-year-olds living in Sweden: Effects of age, SES and home language input on vocabulary production. Journal of Home Language Research, 1, 17-41.


Bohnacker, U., Lindgren, J., & Öztekin, B. (2022). Storytelling in bilingual Turkish-Swedish children: Effects of language, age and exposure on narrative macrostructure. Linguistic Approaches to Bilingualism, 12(4), 413-445.


Chondrogianni, V., Judge-Clayden, F., & Butcher, M. (2022). Majority language vocabulary and nonword repetition skills in children attending minority language immersion education. Applied Psycholinguistics, 43(5), 1073-1107.


Czapka, S., Topaj, N., & Gagarina, N. (2023). Literacy instruction and lexicon size determine bilingual reading development of Russian-German children. International Journal of Bilingualism, 13670069231210716.


dos Santos, C., & Hreich, E. K. (2019). Plurilinguisme au Liban: étude exploratoire du lexique des enfants avec TSA et méthodologie de l'évaluation. In XIXèmes rencontres internationales d'orthophonie: Troubles du spectre de l’autisme, recherche et orthophonie.


Eikerling, M., Andreoletti, M., Secco, M., Luculli, B., Cha, G., Castro, S., ... & Lorusso, M. L. (2023). Remote Screening for Developmental Language Disorder in Bilingual Children: Preliminary Validation in Spanish–Italian Speaking Preschool Children. Applied Sciences, 13(3), 1442.


Eikerling, M., Bloder, T. S., & Lorusso, M. L. (2022). A Nonword Repetition Task Discriminates Typically Developing Italian-German Bilingual Children From Bilingual Children With Developmental Language Disorder: The Role of Language-Specific and Language-Non-specific Nonwords. Frontiers in Psychology 13, 826540. doi: 10.3389/fpsyg.2022.826540.


Gatt, D., Attard, D., Łuniewska, M. & Haman, E. (2017). The effects of bilingual status on lexical comprehension and production in Maltese five-year-old children: a LITMUS-CLT study. Clinical Linguistics and Phonetics, 31(11-12), 844-873.


Haman, E., Łuniewska, M., Hansen, P., Simonsen, H. G., Chiat, S., Bjekić, J., … Armon-Lotem, S. (2017). Noun and verb knowledge in monolingual preschool children across 17 languages: Data from cross-linguistic lexical tasks (LITMUS-CLT). Clinical Linguistics & Phonetics, 31(11-12), 818-843.


Hansen, P., M. Łuniewska, H.G. Simonsen, E. Haman, K. Mieszkowska, J. Kołak and Z. Wodniecka (2019). Picture-based vocabulary assessment vs. parental questionnaires: A cross-linguistic study of bilingual assessment methods. International Journal of Bilingualism, 23(2), 437-456. DOI:


Hansen, P., H. G. Simonsen, M. Łuniewska and E. Haman (2017). Validating the psycholinguistic aspects of CLT: Evidence from Polish and Norwegian. Clinical Linguistics & Phonetics, 31(11-12): 910-930.


Horská, T., & Kapalková, S. (2018). Hodnotenie slovnej zásoby v predškolskom veku. Logopaedica, 20(1), 15 - 19.


Kapalková, S., & Slancová, D. (2017): The vocabulary profile of Slovak children with primary language impairment compared to typically developing Slovak children measured by LITMUS-CLT. Clinical Linguistics & Phonetics, 31(11-12): 893-909.

Khoury Aouad Saliby, C., Dos Santos, C., Kouba Hreich, E., & Messarra, C. (2017). Assessing Lebanese bilingual children: The use of Cross-linguistic Lexical Tasks in Lebanese Arabic. Clinical Linguistics & Phonetics, 31(11-12), 874-892.


Komeili, M., Tavakoli, P., & Marinis, T. (2023). Using multiple measures of language dominance and proficiency in Farsi-English bilingual children. Language Acquisition in Diverse Linguistic, Social and Cognitive Circumstances, volume II, 128.


Lindgren, J. (2019). Comprehension and production of narrative macrostructure in Swedish: A longitudinal study from age 4 to 7. First Language, 39(4), 412-432.


Lindgren, J., & Bohnacker, U. (2020). Vocabulary development in closely-related languages: Age, word type and cognate facilitation effects in bilingual Swedish-German preschool children. Linguistic Approaches to Bilingualism, 10(5), 587–622.


Lindgren, J., & Bohnacker, U. (2022). How do age, language, narrative task, language proficiency and exposure affect narrative macrostructure in German-Swedish bilingual children aged 4 to 6?. Linguistic Approaches to Bilingualism, 12(4), 479-508.


Lindgren, J., Reichardt, V., & Bohnacker, U. (2020). Character introductions in oral narratives of Swedish–German bilingual preschoolers. First Language, 1-29.


Łuniewska, M., Wójcik, M., Kołak, J., Mieszkowska, K., Wodniecka, Z., & Haman, E. (2021). Word knowledge and lexical access in monolingual and bilingual migrant children: Impact of word properties. Language Acquisition.


Pirchio, S., Gatt, D., Passiatore, Y., & Costa, S. (2020). La comunicazione tra insegnanti e bambini bilingui nella scuola dell’infanzia: una ricerca pilota in Italia e a Malta [Communication between teachers and bilingual children in pre-school: a pilot study in Italy and Malta]. Psicologia dell’Educazione, 1-2/2020, 75-92.


Plötner, K. & Rinker, T.  (2020). Lexikalisches Lernen in einer italienisch-deutsch bilingualen Grundschulklasse. In H. Böttger, J. Festman & T. Müller (Eds.), Language Education and Acquisition research. Focusing Early Language Learning, 259-276. Bad Heilbrunn: Klinkhardt.


Polišenská, K., Kapalková, S., & Novotková, M. (2018). Receptive language skills in Slovak-speaking children with intellectual disability understanding words, sentences, and stories. Journal Of Speech, Language, And Hearing Research, 61(7), 1731-1742.


Potgieter, A. P. (2016). Lexical and grammatical development in trilingual speakers of isiXhosa, English and Afrikaans. South African Journal of Communication Disorders, 63(2), 1–11.


Potgieter, A. P., & Southwood, F. (2016). A comparison of proficiency levels in 4-year-old monolingual and trilingual speakers of Afrikaans, isiXhosa and South African English across SES boundaries, using LITMUS-CLT. Clinical Linguistics & Phonetics, 30(2), 87–100.


Ringblom, N., & Dobrova, G. (2019). Holistic Constructions in Heritage Russian and Russian as a Second Language: Divergence or Delay? Scando-Slavica, 65(1), 94–106.


van Zwet, J. L., & Unsworth, S. (2024). Individual differences in structural priming in bilingual and monolingual children: the influence of perspective-taking. Language and Cognition, 1-27. doi:10.1017/langcog.2023.71


Verbeek, L., Kleemans, T., Vissers, C. T., Segers, E., & Verhoeven, L. (2024). Individual variation in bilingual vocabulary in preschoolers with developmental language disorder. Research in Developmental Disabilities, 147, 104695.


CLTs construction steps

Łuniewska, M., Haman, E., Armon­Lotem, S., Etenkowski, B., Southwood, F., Andelkovic, D., ..., Unal - Logacev, U. (2015). Ratings of age of acquisition of 299 words across 25 languages. Is there a cross­linguistic order of words? Behavior Research Methods, 48(3), 1154-1177.


Łuniewska, M., Wodniecka, Z., Miller, C.A., Smolík, F., Butcher, M., Chondrogianni, V., …, Haman. (2019) Age of acquisition of 299 words in seven languages: American English, Czech, Gaelic, Lebanese Arabic, Malay, Persian and Western Armenian. PLoS ONE, 14(8): e0220611.

Wolna, A., Łuniewska, M., Haman, E. et al. Polish norms for a set of colored drawings of 168 objects and 146 actions with predictors of naming performance. Behavior Research Methods 55, 2706–2732 (2023).

Theses which used CLTs

Chyl, K. (2015). Vocabulary Size of Bilingual Preschool Children learning Polish as their first language (Unpublished master’s thesis). University of Warsaw.


Fullana-Garcia, C. (2019). Vocabulary Development in English-Speaking Children with Language Impairment in English Mainstream and Gaelic-Medium Education. (Unpublished master’s thesis), PPLS, University of Edinburgh.


Hansen, P. (2017). In the beginning was the word. A study of monolingual and bilingual children’s lexicons (Unpublished PhD thesis). University of Oslo. 


Judge-Clayden, F. (2020). Lexical and Phonological Skills in Bilingual Children in Immersion Education. (Unpublished undergraduate dissertation). PPLS, University of Edinburgh


Kołak, J. (2020). Language environment and vocabulary development of the Polish-English bilingual children in the United Kingdom and Ireland (Unpublished PhD thesis). University of Warsaw.


Komeili., M (2020). Assessing the Language Abilities of Farsi-English Bilingual Children and the Effects of Internal and External Factors on their language skills (Unpublished doctoral dissertation). University of Reading.


Lindgren, J. (2018). Developing narrative competence: Swedish, Swedish-German and Swedish-Turkish children aged 4-6 (PhD thesis). Studia Linguistica 19. Uppsala: Uppsala University.

Łuniewska, M. (2018). Rozmiar i organizacja słownika umysłowego u dzieci o typowym rozwoju językowym i dzieci z ryzykiem specyficznego zaburzenia językowego SLI [The size and organization of the mental lexicon in typically developing children and children under the risk of specific language impairment] (Unpublished PhD thesis). University of Warsaw.

Markiewicz, S. (2014). Lexical Processing of Nouns & Verbs An Insight into Noun Bias in Polish Monolingual Preschool Children (Unpublished master’s thesis). University of Warsaw.


Montes Salarich, L. (2014) Lexical acquisition in Catalan preschool children (Unpublished bachelor’s thesis). Universitat Autònoma de Barcelona, Bellaterra.


Yılmaz-Çifteci, N. (work in progress). CLT Turkish: Validity and Reliability Study (Unpublished doctoral dissertation). Anadolu University, Eskişehir, Turkey. 


Öberg, Linnéa (2020). Words and non-words: Vocabulary and phonological working memory in Arabic-Swedish-speaking 4–7-year-olds with and without a diagnosis of Developmental Language Disorder (PhD thesis). Studia Linguistica 27. Uppsala: Uppsala University.


Öztekin, Buket (2019). Typical and atypical language development in Turkish-Swedish bilingual children aged 4–7 (PhD thesis). Studia Linguistica 25. Uppsala: Uppsala University.


Potgieter, Anneke Perold (2014). The role of input in the early trilingual acquisition of English, Afrikaans and isiXhosa (PhD thesis). Stellenbosch: Stellenbosch University.


Sirviö, S. (2015). Neljävuotiaiden lasten sanaston taso ja perheen lukutottumukset [Lexical skills of 4-year-olds and shared book reading] (Unpublished master’s thesis). University of Oulu.


Toivola, H. (2015). Kaksivuotiaiden lasten sanasto [Lexical skills of 2-year-olds] (Unpublished master’s thesis). University of Oulu.


Vartiainen, P. (2015). Kolmevuotiaiden lasten tuottavan sanaston taso ja morfologiset taidot [Expressive vocabulary of 3-year-olds and its association to morphosyntactic skills] (Unpublished master’s thesis). University of Oulu.


Yılmaz-Çifteci, N. (2022).  Diller arası sözcük bilgisi testi Türkçe (CLT-TR): Geçerlik ve güvenirlik çalışması. [Cross-linguistic lexical task-Turkish (CLT-TR): Validity and reliability study]. (Unpublished PhD thesis). Anadolu University. 

CLTs are used in research

  • 2020 - ongoing: Polish and Norwegian language and world knowledge development in mono- and multilingual children funded by Norway Grants via National Science Centre (1,500,000 EUR); PIs: Ewa Haman, University of Warsaw & Nina Gram Garmann, Oslo Metropolitan University & MultiLing, University of Oslo
  • 2020 - 2021: Lexical Development of English-Chinese Preschoolers funded by Fullbright Foundation (13 000 USD); PI: Jenny Yichun Kuo, National Chiayi University
  • 2020 - 2021: Supporting children with and without developmental language disorders in Gaelic-medium primary education - Phase II funded by Bord na Gaidhlig - Gaelic Language Board (25 000 GBP); PI: Vasiliki Chondrogianni, University of Edinburgh
  • 2019 - 2023: Tweetalige Ontwikkelingsprofielen funded by Royal Dutch Kentalis; HandicapNL; SIAC; PIs: Lisa Verbek, Ludo Verhoeven, Constance Vissers & Mirjam Blumenthal, Radboud University & Royal Dutch Kentalis
  • 2019 - 2022: Assessing the Narrative and Lexical Abilities of Urdu-Cantonese Bilingual Preschool Children in Hong Kong: Establishing Groundwork on their Family Language (Urdu) Abilities for Improving the Differentiation of South Asian Ethnic Minority Children with and without Language Impairments funded by Hong Kong Research Grants Council (930 000 HKD); PIs: Angel Chan & Saboor Zafar Hamdani, The Hong Kong Polytechnic University
  • 2019 - 2021: Assessing the narrative and lexical abilities of Urdu-Cantonese bilingual preschool children in Hong Kong: Establishing groundwork on their school and community language (Cantonese) abilities for improving the differentiation of South Asian ethnic minority children with and without language impairments funded by The Hong Kong Polytechnic University (756 000 HKD); PIs: Angel Chan & Rachel Kan, The Hong Kong Polytechnic University
  • 2019 - 2021: Interdisciplinary Research Network funded by Berliner Senat (200 000 EUR); PI: Natalia Gagarina, ZAS
  • 2019 - 2021: LITMUS language assessment tests for multilingual children in the Netherlands funded by KF Heinfonds and Utrechts Universiteitsfonds (40 000 EUR); PI: Elma Blom, University of Utrecht
  • 2018 - 2022: MultiMind funded by European Union’s Horizon2020 (255 000 EUR); PI: Tanja Rinker, Catholic University of Eichstätt-Ingolstadt & Maria Luisa Lorusso, Associazione La Nostra Famiglia ‘Istituto Scientifico Eugenio Medea’
  • 2018 - 2021: An application of Chinese Picture Vocabulary Test funded by Ministry of Science and Technology, Taiwan (1 747 000 NT); PI: Jenny Yichun Kuo, National Chiayi University
  • 2017 - 2018: Supporting children with and without developmental language disorders in Gaelic-medium primary education - Phase I funded by Bord na Gaidhlig - Gaelic Language Board (25 000 GBP); PI: Vasiliki Chondrogianni, University of Edinburgh
  • 2015 - 2016: Bilingual assessment of child lexical knowledge: new method for Polish, Czech, Slovak and Hungarian funded by Visegrad Fund (17 060 EUR); PI: Ewa Haman, University of Warsaw
  • 2014 - 2019: BiLI-TAS Language impairment or typical language development? Developing methods for linguistic assessment of bilingual children in Sweden funded Swedish Research Council; PI: Ute Bohnacker, Uppsala University
  • 2013 - 2017: The size and organization of the mental lexicon in typically developing children and children under the risk of specific language impairment funded by the Polish Ministry of Science and Higher Education (200 000 PLN); PI: Magdalena Łuniewska, University of Warsaw
  • 2010 - 2015: Bi-SLI-PL funded by Ministry of Science and Higher Education and National Science Centre; PIs: Ewa Haman, University of Warsaw & Zofia Wodniecka, Jagiellonian University in Kraków
If you would like to

either to develop a new language version of CLTs or to use an existing version in your research, please contact: