This clinical trial aims to determine if a new smartphone-based speech therapy is effective and feasible for patients with post-stroke dysarthria. Participants in the intervention group will use the speech therapy app for 1 hour per day, 5 days per week, over a 4-week period. The control group will receive the same duration and frequency of traditional speech therapy as the intervention group. The study will help us understand if smartphone-based speech therapy is a viable treatment option for post-stroke dysarthria patients.

A total of 76 patients with post-stroke dysarthria will be recruited and stratified by the onset period into acute-subacute (within 6month after index stroke) and chronic (after 6 months after index stroke). Then participants are randomly divided into intervention and control groups.

Patients in the intervention group will be instructed to use smartphone-based speech therapy applications, including oro-motor exercise, phonation, articulation, resonance, syllable repetition, and reading exercises. After the baseline evaluation, treatment goals, and contents will be determined with a speech-language pathologist according to the condition of individual patients. Daily sessions will be provided for 1 hour per day, 5 days per week, over a 4-week period.

Patients in the control group will be instructed to receive traditional speech therapy. Traditional speech therapy can include face-to-face speech therapy, including oro-motor exercises, reading aloud slowly and clearly, and practicing proper breathing and sustained speech. To maintain the same dose and frequency as the intervention group, 60 minutes of treatment will be performed five days a week (e.g., two days of face-to-face speech therapy per week (60 minutes) + three days of self-training through the reading task workbook (60 minutes).

The aim of the study is to establish smartphone-based speech therapy is non-inferior to traditional speech therapy for improving speech intelligibility.

Inclusion Criteria:

1. Aged 18 or over.
2. Neurologically stable stroke patients diagnosed by a stroke specialist neurologist.
3. Diagnosis of dysarthria caused by stroke as confirmed by a stroke specialty neurologist.
4. First-ever stroke patients without previous stroke history.
5. Patients with sufficient cognitive abilities to operate the smartphone-based speech therapy application (Mini-Mental State Exam score ≥ 26)
6. As judged by the neurology specialists: patients with sufficient vision, hearing, communication skills, and motor skills to participate in this study
7. Must have voluntarily understood the trial and signed a consent form agreeing to comply with precautions.

Exclusion Criteria:

1. Co-existing language disorder (e.g., aphasia). Aphasia will be determined by a stroke specialist.
2. Co-existing progressive neurological disorders that can affect dysarthria (e.g., dementia, Pick's disease, Huntington's disease, Parkinson's disease, or Parkinsonism).
3. Diagnosis of severe mental disorders as determined by a clinician (e.g., depression, schizophrenia, alcohol addiction, or drug addiction).
4. Patients taking concomitant medications that could affect the trial results during the study period (e.g., cognitive dysfunction medications, anticholinergics, anti-epileptic drugs, anti-anxiety drugs, antidepressants, antipsychotics, and hypnotics).
5. Patients unable to use/access smartphone technology.
6. Illiterate patients.
7. Patients unable to communicate in Korean.
8. Is unsuitable for participation due to other reasons, as determined by the investigator.
9. Has refused to participate in the study.