Research

I conduct research in several areas listed below. Expand each section to see relevant publications.

* indicates a student co-author.

Language Testing and Assessment

My interest in language testing and assessment is broad, including development, use, and validation of tests for educational and research purposes.

*Coney, N. & Isbell, D. R. (2025). A survey of English language proficiency tests in international student admissions at U.S. research-intensive universities. Language Testing. https://doi.org/10.1177/02655322251348617

*McGehee, M., & Isbell, D. R. (2025). Relationships between English proficiency test scores and academic outcomes: DET, IELTS, and TOEFL in a U.S. public research-intensive university. Studies in Language Assessment.

*Kim, J. & Isbell, D. R. (2024). Test Review: ACTFL Assessment of Performance Toward Proficiency in Languages (AAPPL). Language Assessment Quarterly. https://doi.org/10.1080/15434303.2024.2438983

Isbell, D. R., & Kremmel, B. (2024). Open Science and the next generation of language testing research [Editorial]. Language Testing. https://doi.org/10.1177/02655322241264082

Kremmel, B., & Isbell, D. R. (2024). Open Science practices in language assessment: Introducing the special issue [Editorial]. Language Testing. https://doi.org/10.1177/02655322241264092

Isbell, D. R., *Delaney, M., & *Park, L. (2024). Developing measures of L2 Korean vocabulary knowledge. Vocabulary Learning and Instruction, 13(1), 1-10. https://doi.org/10.29140/vli.v13n1.1227

*Chang, Y.-T., *Choe, A. T., *Holden, D., & Isbell, D. R. (2024). Making each point count: Revising a local adaptation of the Jacobs et al. (1981) ESL COMPOSITION PROFILE rubric. Language Testing, 41(2), 443-455. https://doi.org/10.1177/02655322231217979 

Isbell, D. R., Crowther, D., & *Nishizawa, H. (2024). Speaking performances, stakeholder perceptions, and test scores: Extrapolating from the Duolingo English Test to the university. Language Testing, 41(2), 233-262. https://doi.org/10.1177/02655322231165984

Isbell, D. R., Kremmel, B., & *Kim, J. (2023). Remote Proctoring in Language Testing: Implications for Fairness and Justice. Language Assessment Quarterly, 20(4–5), 469–487. https://doi.org/10.1080/15434303.2023.2288251

*Nishizawa, H., Isbell, D. R., & Suzuki, Y. (2022). Review of the Japanese-Language Proficiency Test. Language Testing. https://doi.org/10.1177/02655322221080898

Isbell, D. R. (2021). Can the test support student learning? Validating the use of a second language pronunciation diagnostic. Language Assessment Quarterly, 18(4),331-356. https://doi.org/10.1080/15434303.2021.1874382

Isbell, D. R., & Son, Y.-A. (2021). Measurement properties of a standardized elicited imitation test: An integrative data analysis. Studies in Second Language Acquisition, 44(3), 859-885. https://doi.org/10.1017/S0272263121000383

Isbell, D. R. (2020). Diagnostic language assessment for L2 pronunciation: A worked example. In O. Kang, S. Staples, K. Yaw, & K. Hirschi (Eds.), Proceedings of the 11th Pronunciation in Second Language Teaching and Learning Conference (pp. 127-140). Iowa State University.

Isbell, D. R., & Kremmel, B. (2020). Test review: Current options in at-home language proficiency tests for making high-stakes decisions. Language Testing, 37(4), 600-619. https://doi.org/10.1177/0265532220943483

Second Language (L2) Speaking

My research on L2 speaking seeks to understand what makes L2 speakers more effective in terms of their overall proficiency, global qualities of speech perceived by listeners (i.e., intelligibility and comprehensibility), and control over specific aspects of phonological features. Sometimes this research has a developmental angle, examining growth or improvement over time resulting from instruction and/or experience.

Crowther, D., & Isbell, D. R. (2023). Second language speech comprehensibility: A research agenda. Language Teaching, 1–17. https://doi.org/10.1017/S026144482300037X

Crowther, D., Isbell, D. R., & *Nishizawa, H. (2023). Second language speech comprehensibility and acceptability in academic settings: Listener perceptions and speech stream influences. Applied Psycholinguistics, 44(5), 858–888. https://doi.org/10.1017/S0142716423000346

Isbell, D. R., & Crowther, D. (2023). Revisiting US Undergraduate Perceptions of Nonnative English Varieties: From Millennials to Generation Z. Applied Linguistics, 44(2), 287-311. https://doi.org/10.1093/applin/amac048

Isbell, D. R., & Lee, J. (2022). Self-Assessment of Comprehensibility and Accentedness in L2 Korean. Language Learning, 72(3), 806-852. https://doi.org/10.1111/lang.12497

Isbell, D. R., & Sakai, M. (2022). Pronunciation assessment in classroom contexts. In T. Derwing, J. Levis, & S. Sonsaat (Eds.), Pronunciation in Second Language Learning and Teaching: Innovations and Developments in Research and Teaching (pp. 194-214). Routledge.

Isbell, D. R., Park, O., & Lee, K. (2019). Learning Korean pronunciation: Effects of instruction, proficiency, L1, and outcome task. Journal of Second Language Pronunciation, 5(1), 13-48. https://doi.org/10.1075/jslp.17010.isb

Isbell, D. R. (2018). Assessing L2 pronunciation for research purposes with listener-based numerical scales. In O. Kang and A. Ginther (Eds.), Assessment in second language pronunciation (pp. 89-111). New York: Routledge.

Loewen, S., & Isbell, D. R. (2017). Pronunciation in face-to-face and oral synchronous computer mediated interaction. Studies in Second Language Acquisition, 39(2), 225-256. https://doi.org/10.1017/S0272263116000449

Technology for Language Learning

In the area of technology for language learning, I am interested in effectiveness of using technological tools in terms of learning outcomes, as well as understanding better how learners make use of technological resources to support their language learning efforts.

Loewen, S., Isbell, D. R., & Sporn, Z. (2020). The effectiveness of app-based language instruction for developing receptive linguistic knowledge and oral communicative ability. Foreign Language Annals, 53(2), 209-233. https://doi.org/10.1111/flan.12454

Gass, S., Winke, P., Isbell, D. R., & Ahn, J. (2019). How captions help people learn languages: A working-memory, eye-tracking study. Language Learning & Technology, 23(2), 84–104.https://doi.org/10125/44684

Loewen, S., Crowther, D., Isbell, D. R., Kim, K. M., Maloney, J., Miller, Z., Rawal, H., & Yin, Y. (2019). Mobile-assisted language learning: A Duolingo case study. ReCALL, 31(3), 293-311. https://doi.org/10.1017/S0958344019000065

Isbell, D. R. (2018). Online informal language learning: Insights from a Korean learning community. Language Learning & Technology, 22(3), 82–102. http://www.lltjournal.org/item/3082

Research Methods and Research Ethics

I believe research methods and research ethics are intertwined: Poor-quality research is difficult to justify from an ethics perspective, and research ethics concerns necessarily influence what research methods we adopt. My work in this area focuses on the appropriate uses of research methods in applied linguistics broadly. I generally view Open Science as critical for advancing research methods and ethics in the field.

Kim, K., Liu, X., Isbell, D. R., & Chen, X. (2024). A comparison of lab and web-based elicited imitation. Studies in Second Language Acquisition. Advance online publication. https://doi.org/10.1017/S0272263124000214

Al-Hoorie, A. H., Cinaglia, C., Hiver, P., Huensch, A., Isbell, D. R., Leung, C., & Sudina, E. (2024). Open science Considerations and issues for TESOL research. TESOL Quarterly, 58(1), 537–556. https://doi.org/10.1002/tesq.3304

Isbell, D. R., & De Costa, P. I. (2024). Ethics in applied linguistics research: Evidence and action [Editorial]. Research Methods in Applied Linguistics, 3, 100104. https://doi.org/10.1016/j.rmal.2024.100104

Plonsky, L., Brown, D., Chen, M., Ghanem, R., Arvizu, M. N. G., Isbell, D. R., & Zhang, M. (2024). “Significance sells”: Applied linguists’ views on questionable research practices. Research Methods in Applied Linguistics, 3(1), 100099. https://doi.org/10.1016/j.rmal.2024.100099

Isbell, D. R., Kim, K. M., & Chen, X. (2023). Exploring the potential of automated speech recognition for scoring the Korean Elicited Imitation Test. Research Methods in Applied Linguistics, 2(3), 100076. https://doi.org/10.1016/j.rmal.2023.100076

Isbell, D. R., & Son, Y.-A. (2023). Explanatory item response models for instrument validation: A tutorial based on an elicited imitation test. Research Methods in Applied Linguistics, 2(3), 100080. https://doi.org/10.1016/j.rmal.2023.100080

Yaw, K., Andringa, S., Gass, S., Hancock, G. R., Isbell, D. R., *Kim, J., Kytö, M., Larsson, T., Plonsky, L., Sterling, S., & Wood, W. (2023). Discussions on the past, present, and future of quantitative research ethics in applied linguistics. Language Teaching, 56(4), 557-561. https://doi.org/10.1017/S0261444823000253

Isbell, D. R., Brown, D., Chen, M., Derrick, D., Ghanem, R., Gutierrez-Arvizu, M. N., Schnur, E., Zhang, M., & Plonsky, L.(2022). Misconduct and questionable research practices: The ethics of quantitative data handling and reporting in applied linguistics. Modern Language Journal, 106(1). https://doi.org/10.1111/modl.12760

Kessler, M., Kasun, G., Isbell, D. R., & De Costa, P. (2021). Methods showcase article: Conducting a netnography in second language acquisition research. Language Learning, 71(4), 1122-1148. https://doi.org/10.1111/lang.12456

Isbell, D. R., & Rogers, J. (2021). Measuring implicit and explicit learning and knowledge. In P. Winke and T. Brunfaut (Eds.), Routledge Handbook of SLA and Language Testing (pp. 305-315). Routledge.