What the research says, and what it doesn't.

The studies were not about English speaking. We read the counts from the abstract on PubMed.

Saunders, T., Driskell, J. E., Johnston, J. H., & Salas, E. (1996). The effect of stress inoculation training on anxiety and performance. Journal of Occupational Health Psychology, 1(2), 170-186.

This is about clinical social anxiety and virtual reality, not a text and voice simulator. It supports graded simulated practice, not a Luwy result.

Chesham, R. K., Malouff, J. M., & Schutte, N. S. (2018). Meta-analysis of the efficacy of virtual reality exposure therapy for social anxiety. Behaviour Change, 35(3).

A small pilot with no comparison group, so it cannot show the practice caused the change.

Premkumar, P., Heym, N., Brown, D. J., Battersby, S., Sumich, A., Huntington, B., Daly, R., & Zysk, E. (2021). The effectiveness of self-guided virtual-reality exposure therapy for public-speaking anxiety. Frontiers in Psychiatry.

Prose passages recalled by university students, not spoken skills. The percentages are from the university's report of the paper.

Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255.

Retention of learned material, mostly in classrooms and labs.

Rowland, C. A. (2014). The effect of testing versus restudy on retention: A meta-analytic review of the testing effect. Psychological Bulletin, 140(6), 1432-1463.

We quote the counts and the direction from the abstract.

Adesope, O. O., Trevisan, D. A., & Sundararajan, N. (2017). Rethinking the use of tests: A meta-analysis of practice testing. Review of Educational Research, 87(3), 659-701.

Mostly classroom studies.

Wisniewski, B., Zierer, K., & Hattie, J. (2020). The power of feedback revisited: A meta-analysis of educational feedback research. Frontiers in Psychology, 10, 3087. Compared with Hattie, J., & Timperley, H. (2007), Review of Educational Research, 77(1), 81-112.

A theory paper with supporting studies, not a single effect size. It explains why Luwy's rewind and side-by-side comparison should work.

Epstude, K., & Roese, N. J. (2008). The functional theory of counterfactual thinking. Personality and Social Psychology Review, 12(2), 168-192.

Verbal recall tasks. The abstract gives no single size of benefit.

Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354-380.

Mixing did not help with vocabulary, so Luwy mixes situations and keeps Word of the day as a plain daily habit.

Brunmair, M., & Richter, T. (2019). Similarity matters: A meta-analysis of interleaved learning and its moderators. Psychological Bulletin, 145(11), 1029-1052.

Figures come from a 2022 review. The studies were in classrooms.

Jeon, E. H., & Kaya, T. (2006). Effects of L2 instruction on interlanguage pragmatic development: A meta-analysis. In J. M. Norris & L. Ortega (Eds.), Synthesizing research on language learning and teaching (pp. 165-211). John Benjamins.

The size of the effect in the later review is quoted by a secondary source. Treat it as a direction, not a promise.

Taguchi, N. (2015). Instructed pragmatics at a glance: Where instructional studies were, are, and should be going. Language Teaching, 48(1), 1-50. Plonsky, L., & Zhuang, J. (2019). A meta-analysis of L2 pragmatics instruction. In N. Taguchi (Ed.), The Routledge handbook of SLA and pragmatics.

Pragmatics here means requests, refusals and politeness. It is not code-switching between languages, and gains are smaller on spontaneous speech than on test items.

Yousefi, M., & Nassaji, H. (2019). A meta-analysis of the effects of instruction and corrective feedback on L2 pragmatics and the role of moderator variables: Face-to-face vs. computer-mediated instruction. ITL - International Journal of Applied Linguistics, 170(2), 277-308.

This shows a link, not proof that reducing anxiety raises results.

Teimouri, Y., Goetz, J., & Plonsky, L. (2019). Second language anxiety and achievement: A meta-analysis. Studies in Second Language Acquisition, 41(2), 363-387.

Classroom studies, mostly on grammar and pronunciation. It is why Luwy asks you to try again instead of just giving you the corrected line.

Lyster, R., & Saito, K. (2010). Oral feedback in classroom SLA: A meta-analysis. Studies in Second Language Acquisition, 32(2), 265-302.

Not about Luwy. It supports the design choice that every scene has a goal the other person is protecting.

Hou, Z., & Min, S. (2026). Dialogue-based computer-assisted language learning systems for second language speaking development: A three-level meta-analysis. ReCALL, 38(1). Published online 14 July 2025.

A small lab experiment. It shows that a reacting audience creates pressure, not that practising with one lowers anxiety later. The full text is paywalled.

Pertaub, D.-P., Slater, M., & Barker, C. (2002). An experiment on public speaking anxiety in response to three different types of virtual audience. Presence: Teleoperators and Virtual Environments, 11(1), 68-78.

Mostly lab tasks that judge emotions or lies from video or audio, not live conversation. The page we link shows the citation only.

Blanch-Hartigan, D., Andrzejewski, S. A., & Hill, K. M. (2012). The effectiveness of training to improve person perception accuracy: A meta-analysis. Basic and Applied Social Psychology, 34(6), 483-498.

This shows a link, not proof that improving this skill causes better outcomes.

Hall, J. A., Andrzejewski, S. A., & Yopchick, J. E. (2009). Psychosocial correlates of interpersonal sensitivity: A meta-analysis. Journal of Nonverbal Behavior, 33(3), 149-180.

Mostly in-person workplace courses, not AI practice. The interpersonal figures come from the paper's table, not its abstract. The link is a university-hosted copy.

Arthur, W., Jr., Bennett, W., Jr., Edens, P. S., & Bell, S. T. (2003). Effectiveness of training in organizations: A meta-analysis of design and evaluation features. Journal of Applied Psychology, 88(2), 234-245.

A narrative review of mostly clinical populations. It supports 'assertiveness can be trained', not any effect size for Luwy or for students.

Speed, B. C., Goldstein, B. L., & Goldfried, M. R. (2018). Assertiveness training: A forgotten evidence-based treatment. Clinical Psychology: Science and Practice, 25(1), 1-20.

Medical procedural skills, not conversation. We cite it for the principle of simulation plus deliberate practice, and the authors call the sample modest.

McGaghie, W. C., Issenberg, S. B., Cohen, E. R., Barsuk, J. H., & Wayne, D. B. (2011). Does simulation-based medical education with deliberate practice yield better results than traditional clinical education? A meta-analytic comparative review of the evidence. Academic Medicine, 86(6), 706-711.

Mostly classroom studies, not speaking. The numbers are from the paper body, not the abstract. It does not test single-habit practice against general practice.

Hattie, J., & Timperley, H. (2007). The power of feedback. Review of Educational Research, 77(1), 81-112.

Goals were mostly health, exercise and study tasks, not conversation skill. We use it for the closing next step in your plan, not for speaking gains.

Gollwitzer, P. M., & Sheeran, P. (2006). Implementation intentions and goal achievement: A meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69-119.

Gains are larger on controlled tasks such as reading aloud than on spontaneous speech. We could not confirm that tongue-twister drills were included, so this does not prove them.

Lee, J., Jang, J., & Plonsky, L. (2015). The effectiveness of second language pronunciation instruction: A meta-analysis. Applied Linguistics, 36(3), 345-366.

Attendance was voluntary, so this is an association, not proof that coaching caused the gain. Promotion interviews in public services, not graduate hiring.

Maurer, T. J., Solamon, J. M., Andrews, K. D., & Troxtel, D. D. (2001). Interviewee coaching, preparation strategies, and response strategies in relation to performance in situational employment interviews. Journal of Applied Psychology, 86(4), 709-717.

A conference paper on a research prototype with face and voice analysis. No effect size or anxiety measure in the abstract, and not tested on text or LLM-based coaches.

Hoque, M. E., Courgeon, M., Martin, J.-C., Mutlu, B., & Picard, R. W. (2013). MACH: My Automated Conversation coacH. Proceedings of UbiComp '13, 697-706. ACM.

A reading and listening test, not a speaking test.

EF Education First (2025). EF English Proficiency Index 2025, Malaysia fact sheet.

A small interview study. We use it for the distinction, not for a percentage.

Ting, S.-H., Marzuki, E., Chuah, K.-M., Misieng, J., & Jerome, C. (2017). Employers' views on importance of English proficiency and communication skill for employability in Malaysia. Indonesian Journal of Applied Linguistics.

One university, a student research report. Only the abstract is public, so we quote the abstract only.

Tie, W. L. (2020). A study of English speaking anxiety among tertiary students in a Malaysian public university. Universiti Malaysia Sarawak.

60 students answered a questionnaire and 6 were interviewed. Small and from one university.

AlShaibani, G., Fong, Y. A., Ravindran, L., & Al-Shaibani, G. K. S. (2022). Oral presentation anxiety among undergraduate Malaysian Chinese students in a private university. ASEAN Journal of Teaching and Learning in Higher Education.

A survey at one university. It shows links between worry and confidence, not what reduces them.

Kho, M. G.-W., Ting, S.-H., & Dumin, W. (2025). Language anxiety symptoms, self-efficacy, and willingness to communicate among Malaysian university students. Indonesian Journal of Applied Linguistics, 15(2).