Exploratory Trial of the "HiDongDong" Language Rehabilitation App for Articulation Delay.

This exploratory randomized controlled trial (RCT) evaluates the effectiveness of the AI-based application "HiDongDong" in improving articulation in children aged 2 to under 14 years with suspected articulation delays.

1\. Study Methods

1. Screening and Enrollment Children suspected of articulation developmental delay will be assessed for eligibility according to predefined inclusion and exclusion criteria. Eligible participants will be enrolled, randomized, and scheduled for study visits.
2. Visit 1 - Baseline Assessment

At the first visit, a blinded assessor will collect demographic data (child's age, sex, and underlying medical conditions) and conduct a single baseline assessment, including the following:
* Language assessments: U-TAP (Urimal Test of Articulation and Phonology)

* SELSI (Sequenced Language Scale for Infants) or PRES (Preschool Receptive- Expressive Language Scale)
* Functional independence: WeeFIM (Functional Independence Measure for Children)
* Caregiver emotional status: Satisfaction (5-point Likert scale), depression (BDI; Beck Depression Inventory), anxiety (BAI; Beck Anxiety Inventory)
* Clinician satisfaction: 5-point Likert scale
3. Post-Assessment Procedures Following baseline assessment, the control group will be discharged and return home. For the intervention group, a personalized language training program will be generated based on the results of the HiDongDong assessment.
4. Training and Orientation Participants in the intervention group will receive instruction on how to use the HiDongDong language training program, along with guidance on the study procedures.
5. Intervention Period The intervention group will complete the HiDongDong language training program at home under caregiver supervision for 4 weeks, 5 sessions per week, 20 minutes per session. Adherence will be monitored throughout the intervention period. The control group will receive language training provided by a speech-language pathologist.
6. Visit 2 - Post-Intervention Assessment and Study Completion Four weeks after the intervention, both the control and intervention groups will undergo a single post-intervention assessment conducted by a blinded assessor. Upon completion of the assessment, follow-up will be concluded.

2\. Comparator and Randomization Participants will be randomized by an independent statistician affiliated with the Medical Research Collaborating Center of the Biomedical Research Institute at Seoul National University Bundang Hospital (SNUBH), using SAS version 9.4.

Assessor blinding will be applied. A blinded assessor (e.g., a hospital-based speech-language pathologist) will conduct all assessments without knowledge of each participant's group allocation, in an independent time and setting.

The sole difference between the two groups is the provider of the intervention:

* Control group: Language training delivered by a speech-language pathologist
* Intervention group: Language training delivered via the HiDongDong application (investigational medical device)

Participants will return after 4 weeks for post-intervention assessment by a blinded assessor, after which follow-up will be concluded.

To prevent interim analysis, assessment results will not be disclosed to any study personnel until the dataset is complete.

• HiDongDong Intervention (Device): Participants will receive a 4-week individualized articulation training program delivered via the AI-based HiDongDong application. Training is conducted at home under caregiver monitoring, 5 sessions per week, 20 minutes per session. Exercises are tailored to each child's articulation needs based on baseline assessment using U-TAP and the study-specific word list. Adherence and engagement will be monitored.
• Standard Care / Speech Therapist Intervention (Behavioral): Participants will receive standard articulation training conducted by a certified speech-language therapist. Outcome assessments will be conducted at the same time points as the experimental group for comparison.

Primary outcomes

• Consonant accuracy (%) and vowel accuracy (%) assessed via U-TAP [Baseline and post-intervention (4 weeks)]: Korean Articulation and Phonology Assessment (U-TAP). Changes in articulation accuracy will be evaluated following the 4-week HiDongDong intervention compared to the control group. A blinded speech-language therapist will present picture stimuli, and children's consonant and vowel production will be analyzed at word and sentence levels to identify misarticulations and error patterns.

Other outcomes

• Receptive language score measured by SELSI [Baseline and post-intervention (4 weeks)]: Receptive language ability is assessed using the Sequenced Language Scale for Infants (SELSI). Higher scores indicate better receptive language comprehension ability.
• Receptive language score measured by PRES [Baseline and post-intervention (4 weeks)]: Receptive language ability is assessed using the Preschool Receptive-Expressive Language Scale (PRES). Higher scores indicate better receptive language comprehension ability.
• Expressive language score measured by SELSI [Baseline and post-intervention (4 weeks)]: Expressive language ability is assessed using the Sequenced Language Scale for Infants (SELSI). Higher scores indicate better expressive language ability.
• Expressive language score measured by PRES [Baseline and post-intervention (4 weeks)]: Expressive language ability is assessed using the Preschool Receptive-Expressive Language Scale (PRES). Higher scores indicate better expressive language ability.
• Functional Independence (WeeFIM) [Baseline and post-intervention (4 weeks)]: Total score (18-126 points) across 6 domains and 18 items assessing functional independence in daily living activities; higher scores indicate greater independence.
• Caregiver Satisfaction [Baseline and post-intervention( 4 weeks)]: Caregiver satisfaction assessed using a 5-point Likert scale; higher scores indicate greater satisfaction.
• Caregiver Depression(Beck Depression Inventory) [Baseline and post-intervention (4 weeks)]: Caregiver depression assessed using the Beck Depression Inventory (BDI); total score ranges from 0 to 63, with higher scores indicating more severe depressive symptoms.
• Caregiver Anxiety(Beck Anxiety Inventory) [Baseline and post-intervention( 4 weeks)]: Caregiver anxiety assessed using the Beck Anxiety Inventory (BAI); total score ranges from 0 to 63, with higher scores indicating more severe anxiety symptoms.
• Clinician Satisfaction [Baseline and post-intervention( 4 weeks)]: Clinician satisfaction assessed using a 5-point Likert scale (1-5); higher scores indicate greater satisfaction.

Sex: All, ages: 2 Years to 13 Years

Inclusion Criteria:

1. Children aged 2 years to under 14 years
2. Persistent difficulties in speech sound production, or reduced speech intelligibility that interferes with communicative participation, resulting in limitations in social participation, academic performance, or daily activities
3. Articulation developmental delay suspected based on U-TAP results, with articulation performance more than 1 standard deviation below the mean for the same age group (-1SD)
4. Sufficient cognitive ability to follow simple instructions via a mobile device (tablet)
5. For children under 7 years of age: a caregiver who has received sufficient explanation of the study purpose and procedures and has voluntarily provided written informed consent
6. For children aged 7 years or older: voluntary assent from the child after sufficient explanation of the study purpose and procedures by the investigator,

in addition to written informed consent from the caregiver

Exclusion Criteria:

1. Caregiver or child does not consent to study participation, or withdraws consent during the study
2. U-TAP results indicate articulation development within the normal range, with no suspicion of articulation developmental delay
3. Difficulty understanding simple instructions or participating in assessments and training due to moderate or severe cognitive impairment, attention deficit, autism spectrum disorder, or similar conditions
4. Significantly limited speech production due to neuromuscular or anatomical causes, including severe visual impairment or visual field deficits, hearing impairment, cleft palate structural abnormalities, or severe oral/facial muscle dysfunction, resulting in difficulty with articulation
5. Inability to continue study participation due to acute illness or other conditions that may affect assessment or training during the study period, or unwillingness of the caregiver or child to continue participation
6. Determination by the principal investigator that study participation may pose a risk to the safety or well-being of the child

Any one of the above exclusion criteria is sufficient for exclusion.