Melodic intonation therapy in a Polish-speaking adolescent with developmental language disorder: a clinical case report

Introduction

Specific language impairment (SLI), increasingly referred to as developmental language disorder (DLD), is characterized by persistent deficits in language acquisition that cannot be explained by intellectual disability, hearing loss, or other neurological conditions (Leonard 2014; Bishop 2017; Bishop et al. 2017). Children with SLI/DLD typically demonstrate marked difficulties in phonology, morphology, and syntax, despite displaying intact non-verbal intelligence. Cross-linguistic studies have highlighted that the manifestation of SLI/DLD can vary by language; for example, while English-speaking children often struggle with tense and agreement morphology, Polish-speaking children are more likely to show deficits in inflectional morphology and complex syntactic structures. Such differences underscore the importance of considering linguistic context when evaluating and treating SLI/DLD.
Language impairments such as aphasia and SLI/DLD manifest differently across different languages. English and Polish differ in morphosyntactic and phonological structures. English is an analytic language with a fixed word order and opaque orthography. Polish is synthetic, with a flexible word order and rich inflectional morphology. These languages differ typologically, and such contrasts affect impairment profiles. English speakers often make word-order errors by omitting auxiliary verbs. Polish speakers frequently omit case endings, make gender agreement errors, and simplify syntax (Leonard 2014; Smoczyńska et al. 2015; Kielar et al. 2016; Łuniewska 2018).
Research not only provides evidence about shared patterns, such as reduced sentence complexity, word retrieval difficulties, but also pragmatic deficits and language-specific vulnerabilities, such as simplification of syntax and omission of functional words in English aphasic patients, and in Polish aphasic patients who struggle with inflectional morphology and phonological clusters (Grabowski 2019).
Recent studies by Lally et al. (2025) and Meir and Armon-Lotem (2017) point out that although bilingual SLI assessment should consider both structural differences as diagnostic markers in one language, they might not be applicable in another. These studies concerned Polish-English bilingual children.
Melodic intonation therapy (MIT) was originally developed for patients with severe non-fluent aphasia (Helm-Estabrooks et al. 1989). The theoretical basis of MIT is grounded in the use of melodic intonation, rhythmic pacing, and left-hand tapping to facilitate speech production. These elements are believed to engage right-hemisphere networks and music-related pathways to support language recovery when traditional left-hemisphere regions are impaired (Schlaug 2016). The key mechanisms proposed for MIT include: (a) rhythmic structuring to enhance temporal processing and articulatory planning, (b) intonation patterns that reduce speech motor complexity and scaffold prosody, and (c) multimodal integration through simultaneous hand tapping to strengthen sensorimotor coupling. Substantial evidence supports MIT’s efficacy in post-stroke aphasia rehabilitation, including improvements in verbal fluency, repetition, and functional communication (Schlaug et al. 2008, 2010; Tabei et al. 2016; Van der Meulen et al. 2016; Wanicharoen et al. 2024). A recent study by Wanicharoen et al. (2024) after MIT reported “significantly improved speech recovery, precise language repetition, and functional communication in patients with non-fluent aphasia”.
Although MIT has been studied primarily in acquired aphasia, there is emerging interest in its potential application to developmental disorders. Riemersma’s (2018) critical review emphasized the promise of intonation-based interventions for children with speech and language disorders, highlighting overlaps between rhythmic-melodic training and the linguistic deficits observed in DLD. Furthermore, rhythm- and music-based interventions have been shown to support syntactic processing and reading development in children with language and learning disorders (Przybylski et al. 2013; Habib et al. 2016). These findings suggest that the mechanisms underpinning MIT – particularly rhythmic entrainment and prosodic scaffolding – may be relevant not only to aphasia but also to developmental contexts.
Given these considerations, the present analysis aimed to explore the feasibility of applying MIT in a Polish-speaking adolescent with SLI/DLD. To our knowledge, this represents one of the first attempts to extend MIT beyond its traditional use in acquired aphasia to a developmental language disorder. This cross-linguistic case study is particularly important, as Polish presents a distinct morphological and syntactic profile compared to English, offering a unique opportunity to examine how MIT may interact with the linguistic characteristics of SLI/DLD in different languages.
This case study is novel in applying MIT, traditionally used in aphasia (Helm-Estabrooks et al. 1989; Schlaug et al. 2008, 2010; Schlaug 2016; Zumbansen et al. 2014; Wanicharoen et al. 2024), to a developmental disorder context. The so-called specific language impairment affects approximately 7-10% of children in the world (Leonard 2006, Hu et al. 2025). Polish speech therapists and psychologists have estimated that about 300,000 children aged 4-14 suffer from SLI in Poland (Prajsner 2013) and do not receive help, often ending up in special schools with programmes tailored to the needs of children with various types of intellectual disabilities.
Although children with SLI develop properly in the non-verbal sphere, their level of language development noticeably differs from their non-verbal intelligence; hence, these children have difficulty with speech and communication. They cannot build coherent, complex sentences or formulate correct phrases and expressions. Consequently, although the observed language deficit does not correlate with the intellectual deficit (Stark and Tallal 1988; Bishop 2008), it may adversely affect children suffering from with disorder emotionally, limiting their communicative abilities. The above-mentioned lack of intellectual deficits allows the children and young people to be aware of their deficits and may bring about the development of two extreme, contradictory attitudes as a result.
The first approach could be to adopt an attitude resulting in withdrawing from any social activity requiring the construction of spoken words, which may lead to dysthymia and the development of depressive or conduct disorders. The second approach is to display confrontational behaviour when experiencing difficulties forming correct expressions, recalling words, responding to questions or in any situations that reveal their problem to others.
The challenge of taking the specific needs of the individual child who has suffered from neglect in an underprivileged environment into consideration in a society where there is a lack of multi-professional care and where up to 80% of children affected by SLI will not have a chance to make up for the delays in their development is considerable. As a result, the problem will be transferred and affect the entire education period and the life of a person with SLI. Approximately 40% of people who suffered from SLI when they were children, read at a basic level or below that level when they reach adulthood; their social relations are increasingly rare or abnormal, they stand a lower chance of developing their competencies and become increasingly hostile to their environment, shrinking from forming relationships with their own children.
Hypothesis: MIT engages rhythmic/melodic processing to support phonological-motor planning in Polish SLI/DLD.
The aim of the case study was to examine the effect of MIT (Helm-Estabrook et al. 1989) in an adolescent diagnosed with SLI/DLD. The focus of the paper is to discuss changes observed in the behaviour and speech performance of the patient.
Intervention planning was informed by the principles of natural phonology (NP), a theory of phonological development proposed by Stampe (1969/1979) and subsequently elaborated by Ingram (1989). Natural phonology views phonological processes as universal, natural patterns that are gradually suppressed as the child’s linguistic system matures. In children with SLI/DLD, the persistence of such processes beyond the expected developmental period may contribute to atypical phonological profiles, disrupted morphophonological patterns, and limited intelligibility.
From a therapeutic perspective, NP emphasizes that intervention must not be based on rigid universal rules but rather on the child’s current phonological system, communicative context, and functional needs. This framework prioritizes functional balance between linguistic form and communicative function, with therapy aiming to gradually restructure the phonological system to enhance communicative effectiveness. The approach also highlights the importance of tailoring intervention to the linguistic environment – in this case, Polish – where rich inflectional morphology and complex consonant clusters create additional challenges for children with SLI/DLD.
In the present case, NP served as a guiding framework for selecting therapeutic materials and designing MIT adaptations. By combining the rhythm- and melody-based elements of MIT with NP’s emphasis on individualized, context-dependent phonological restructuring, the intervention sought to reinforce both prosodic and segmental aspects of speech. This integrative approach was intended to support the participant’s gradual suppression of persistent phonological processes while strengthening his functional ability to produce morphosyntactically appropriate utterances in everyday communication.

Case report

A 16-year-old male was diagnosed as suffering from SLI/DLD at age 7 on the basis of standardized speech-language assessments. The author did not have access to the complete medical records of the adolescent, and was unaware of the exact timing of the diagnosis, as well as the precise tools used for the diagnosis. The only information made available to the author was provided in paper form. The diagnosis was reconfirmed at age 16 prior to his enrolment in the present study. Despite receiving twice-weekly school-based speech therapy, no measurable improvement was observed in his language performance.
The participant underwent two neuropsychological evaluations: the first prior to initiation of MIT, and the second after six months of intervention. The AFA-skala (AFA Scale; Paluch et al. 2012), an aphasia assessment tool, validated for Polish populations, was used to assess comprehension, repetition, naming, conversational responses, and spontaneous speech. The participant’s language impairment was classified as moderate according to standardized benchmarks.
The rehabilitation programme was a modified version of the MIT programme. The modified MIT protocol incorporated rhythmic left-hand tapping, slowed melodic intonation patterns, and simplified pacing to match the patient’s abilities. The modification consisted solely of adapting the programme to the patient’s capabilities. The training was shorter than in the original protocol, and training sessions took place 3-5 times a week rather than daily. We administered the treatment 3-5 days/week, 0.5-1 hours/day (a less stringent procedure than in the original protocol, which was the only modification) for a total of 74 hours of intervention over 6 months. In view of NP, the situation of each patient with DLD should be analysed individually, and selected material and applied methods should be tailored to the needs and capacities of a patient to obtain a functional balance between form and function (Donegan and Stampe 1979). Therefore, NP is regarded as a guiding framework; however, intervention must be individualized. A holistic approach offered within the NP is the essence of what patients with DLD need, in light of the theory of user language perceived in the context and within their language behaviour. There is, therefore, no doubt about the existence of absolute rules that would allow each of these patients to be considered within the same framework. Therapeutic materials and strategies were selected according to the participant’s specific needs to achieve functional balance between linguistic form and communicative function.
On the one hand, the patient was motivated to attend sessions; on the other, the difficulties he faced created barriers at the various stages required for participation in the training. There were problems with the preliminary pre-intervention examination. The patient had numerous problems adjusting to and complying with the rules and principles laid down by the diagnostician and then by the therapist. Each difficulty encountered by the patient was characterised by a symptomatic reluctance to make an effort, accompanied by outbursts of anger and uncooperative behaviour directed toward those conducting the intervention. The patient interrupted the tests, leaving the room where the initial test was being held. A pattern of behaviour emerged: he would slam the door when he was clearly upset in response to the problems he was facing, and he was easily discouraged.
He had serious difficulties that stemmed from his language-related challenges such as selecting appropriate words (retrieval and recall deficits), describing pictures, naming objects, imitating presented stimuli, and initiating any spontaneous speech.
During initial assessments, the participant demonstrated difficulties complying with testing procedures. He occasionally terminated tasks prematurely, left the testing environment, or displayed signs of frustration including refusal to continue and episodes of overt anger. These behaviours appeared to be elicited by task demands exceeding his tolerance.
Prior to the intervention, the participant exhibited deficits in lexical retrieval and recall, picture description, object naming, imitation of verbal stimuli, and spontaneous speech. Interviews with his school-based speech therapist indicated that he was raised in a disadvantaged socio-economic context and exhibited difficulties in peer interactions, largely attributable to impulsive behaviours and memory-related deficits. When unable to retrieve target words, the participant frequently displayed heightened arousal and disproportionate emotional reactions.
Interviews with a speech therapist working in the school and with the boy revealed that he came from a neglected intellectual environment and a family with low socio-economic status. He had considerable problems functioning in the peer group due to his displays of impulsive behaviour and problems recalling things. When he could not recall a word, the boy became angry; his level of arousal increased rapidly, and his reactions were disproportionately violent or inappropriate for the situation. Over the course of therapy, his compliance improved. After some time, he began to attend sessions with greater commitment. Soon, certain effects and changes showing progress also appeared. The principal indicators of functional improvement were his consistent engagement and observable satisfaction during treatment sessions. After approximately 9 sessions, the level of his language function and general behaviour gradually began to undergo a slight improvement, and he exhibited increased engagement and stable participation. After 74 training sessions, this boy was among the patients who benefited most from MIT, as confirmed by an assessment performed the end of the intervention using the AFA Scale (Paluch et al. 2012; Paluch and Drewniak-Wołosz 2022).
The AFA Scale is a questionnaire used to evaluate the speech of children with aphasia. It is also helpful when assessing children with suspected speech disorders. The AFA Scale reviews speech comprehension and expression, repetition, verbal and non-verbal responses, spontaneous speech, and the ability to comprehend instructions and sentences. It is a qualitative assessment tool that allows the speech-language therapist to present findings that characterise linguistic features. The results form the basis for creating an individualised speech and language therapy programme. The scale was used to assess the results of the children involved in the project before and after the intervention. No data were recorded that would allow for a quantitative objective assessment, as data collection in this case is based mainly on a qualitative assessment of results.

Results

Although the patient did not make observable progress in speech during the training sessions, he meaningfully improved his behaviour, and finally also attained better results in neuropsychological tests and was more able to produce speech spontaneously.
He was more focused and able to take part in training sessions more patiently, to react properly during speech imitation tasks, and to retrieve and recall words, etc. In addition to participating in the sessions, he began to spontaneously make conversation with people, engaging in discussions with the therapist. It should be noted that throughout the intervention period, the patient only participated in the initial stage of the therapy, as he was unable to achieve 90% in five of the following production sessions required by the authors of the method to change the therapy level. However, the most important and marked improvement was reported at the end of the intervention.
During pre- and post-intervention tests examining language functions, the following aspects were examined: comprehension, repetition, naming, conversation, ability to describe pictures, and spontaneous speech.
Across the intervention period, gradual improvement was observed in both language performance and behavioural regulation.
We found that post-intervention neuropsychological assessment showed notable change, as the patient was able to produce more words independently. During the pre-intervention assessment, he needed support in all attempts to produce words, which was not the case after the intervention. Post-therapy testing with the AFA Scale confirmed meaningful improvements in repetition, naming, conversation, picture description, and spontaneous speech.
Table 1 shows pre- and post-intervention differences using the AFA Scale to evaluate the patient’s performance.

Discussion

The patient showed improvements in repetition, naming, conversational speech, and spontaneous speech, while comprehension remained stable – likely due to an intact baseline or MIT’s limited impact on comprehension. Improvement in repetition, naming, conversational speech, and spontaneous speech depends on already well-described mechanisms such as rhythmic pacing and melodic prosody, and these mechanisms may explain the observed gains.
With regard to comprehension, given that SLI involves developmental deficits in language acquisition, and MIT was developed for acquired expressive language deficits (e.g., in aphasia), its application here may not have addressed the comprehension challenges specific to SLI. The lack of improvement in comprehension may be due to different reasons. It may be partly due to a ceiling effect, as the participant’s comprehension was largely intact before the intervention, limiting the assessment tool’s ability to detect further gains. It is also possible that comprehension improvements were too subtle to be captured by the assessment tool used, or that they emerged more slowly than expressive improvements. Alternatively, MIT’s focus on expressive language may not adequately target the underlying comprehension deficits characteristic of SLI. The lack of sensitivity in the assessment or the slower trajectory of receptive improvements may therefore account for the outcome.
The novelty of the study lies in applying MIT in Polish to a developmental disorder.
Limitations include the single-case design, the lack of statistical analysis, and the constraints of the assessment tools used. Nevertheless, the findings support potential benefits of rhythm- and music-based interventions in DLD, which corroborates the findings of previous studies (Przybylski et al. 2013; Habib et al. 2016; Riemersma 2018; Popescu et al. 2022; Wanicharoen et al. 2024; Hossain et al. 2025).

Conclusions and implications

Scientists involved in research on DLD agree that if the disorder is not detected early enough, this vulnerability may lead to underachieving at school. Unless such academic failure, together with various other adverse conditions, is confronted effectively through intervention, this may negatively affect the person throughout their life (Krasowicz-Kupis 2012). Both withdrawal and behavioural disorders lead to disturbances caused by an inability to function normally in social settings in daily life, in the family, at school, or at work. In contrast, a prompt and correct diagnosis could provide opportunities to reduce the negative impacts of this disorder on a child’s development and resultant functioning during the course of their life.
The case of our patient is interesting, as during the initial intervention, the patient was at a stage when almost all other problems were present. He was uncooperative and resisted any attempts to help or support him; he was resigned and envisaged no hope for change. Furthermore, the environment around him was unsupportive, as his behaviour was perceived as unacceptable.
The results achieved in our patient are interesting from several points of view: Firstly, the results shed a new light on the MIT and its effectiveness. Although our patient did not improve meaningfully during intervention sessions, as he spent a lot of time arguing, crying, and presenting offensive and uncooperative behaviours, gradually, over time, he was able to attend sessions with attention and commitment. Secondly, although the patient still needed assistance and was unable to perform at intermediate and advanced levels (according to the steps described in “Melodic Intonation Therapy” by Helm-Estabrook et al. 1989) during intervention sessions, the improvement of his memory was noticed by clinicians, and while referring to the pre- and post-intervention neuropsychological assessment and meaningful improvement, this was also reported at the level of lexical retrieval outside of intervention sessions. Thirdly, although the patient still needed help in speech performance, he performed much more calmly and was more focused on the speech tasks than on negative behaviours. Family members, teachers, and the therapist noticed a steady improvement in the patient’s performance, although the post-intervention assessment was not repeated.
The degree of improvement in neuropsychological assessment was meaningful to speech therapists, clinical psychologists, and to the patient himself. Finally, after completing the training sessions, our patient’s spontaneous speech continued to become increasingly fluent, as noted during follow-up visits conducted three times at monthly intervals after the training ended.
Our data raise a question about the most vital component of the intervention, which was crucial in this case. Although MIT has been primarily applied in post-stroke aphasia, several mechanisms may account for its positive effects in the present case of a child with SLI/DLD. First, the rhythmic and temporal structuring inherent to MIT may ease speech segmentation and articulatory planning, compensating for temporal processing deficits often observed in children with DLD. Second, MIT engages melodic and intonational processing, thereby activating right-hemisphere networks that may support compensatory language reorganization. Third, the integration of prosody with articulatory motor movements (e.g., rhythmic hand tapping) provides multimodal support, reinforcing phonological-motor planning and execution. Fourth, the motivational and emotional qualities of music may enhance engagement, reduce frustration, and sustain participation – factors of relevance given the patient’s initial oppositional behaviours. Finally, although systematic studies of MIT in DLD are lacking, converging evidence suggests that rhythm- and music-based interventions can benefit language and communication in developmental disorders. For example, Przybylski et al. (2013) demonstrated that rhythmic auditory stimulation facilitated syntactic processing in children with DLD, and Habib et al. (2016) reported improved reading and language-related functions in children with dyslexia following music-based training. Together, these mechanisms and converging findings may explain why MIT yielded observable improvements in this case, and they highlight the potential value of extending MIT and related interventions to developmental language disorders. More studies are needed to confirm our results and explain the effect seen in the case study.
Written informed consent was provided by both the participant and his legal guardian, in accordance with Polish law and ethical guidelines, prior to his inclusion in the study.

Acknowledgments

The author would like to thank Nigel Axworthy, who reviewed the paper, for his support.

Disclosures

This research received no external funding.
Institutional review board statement: The project was approved by the Ethical Committee for Research Projects of the Institute of Psychology, Adam Mickiewicz University, Poznań, on 7.06.2011.
The author declares no conflict of interest.

References