Cross-cultural insights into Melodic Intonation Therapy: a systematic review on non-English applications

Background and Aims Melodic Intonation Therapy (MIT) is an established intervention for post-stroke non-fluent aphasia. It was developed for English speakers, and its adaptation to other languages has not been systematically examined. This review aimed to identify the languages in which MIT has been adapted, synthesise the modifications introduced, evaluate clinical outcomes across language domains, and propose an evidence-informed cross-linguistic adaptation framework.Methods A systematic review following PRISMA 2020 guidelines searched nine databases, including PubMed, Scopus, Embase, PsycINFO, CINAHL, Medline, Web of Science, CSCD and KCI. Studies applying the adapted MIT to non-English-speaking adults with post-stroke non-fluent aphasia were included. Risk of bias was assessed using RoB 2, ROBINS-I, and JBI checklists. Data were synthesised narratively, organised by prosodic typological category.Results Twenty-one studies (1983–2025) met the inclusion criteria: 7 randomised controlled trials (RCTs), 1 non-randomised controlled study, 5 case series, and 8 case reports, comprising 285 participants. MIT was delivered across 10 languages, including Mandarin Chinese (n = 5), Dutch (n = 4), and Japanese (n = 3). Intervention durations ranged from 9 days to 16 weeks, with session intensity from twice weekly to daily. Adaptations included tonal preservation, rhythmic restructuring, and culturally relevant phrase construction. Across designs and typologies, repetition, especially treatment-proximal material, showed the most consistent improvement, whereas functional communication and participation outcomes were infrequently assessed and more variable. The risk of bias was mixed; several RCTs were rated as high risk, primarily due to deviations from intended interventions, missing data, and reporting limitations.Conclusion MIT has been adapted across ten non-English languages spanning four prosodic typological categories, though the evidence base is concentrated in Dutch and Mandarin and remains methodologically heterogeneous. Adaptations differ substantially in how rhythmic and pitch-related components are operationalised. The most reliable outcome signal is improvement in repetition, especially for trained/proximal material, while conclusions regarding functional communication, generalisation, and long-term effects are constrained by limited measurement and follow-up. An evidence-informed six-component cross-linguistic adaptation framework is proposed to support reproducible future adaptations.