DLDVOCAB+NCT06935851
Effect of Phonotactic Probability and Orthography on Vocabulary Learning
A study testing VOCAB + in people with DLD, run by Arizona State University at 1 site in United States.
Trial summary
The purpose of the study is to investigate how phonotactic probability) and orthography affect vocabulary by children with low oral language levels. The investigators will use a 2 x 2 within-subjects factorial design where every participant receives the treatment. Read more about this study
- Who is it for?
- Ages 8 to 9 yearsHealthy volunteers can take part
- Conditions the study is for
- DLD
- What is being tested?
- VOCAB +
- Type of treatment
- Pill or oral medicine, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 23 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Feb 2025to 25 Apr 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 9 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Enrolled in or just completed third grade.
Who cannot join
- Any diagnosis of sensory impairments A diagnosis of autism or traumatic brain injury
Trial locations and contacts
1 site in 1 country.
United States1 site
Osborn District School Encanto
Phoenix, Arizona, 85013
About this study
Official title: The Effect of Phonotactic Probability and Orthography on Vocabulary Learning
The purpose of the study is to investigate how phonotactic probability) and orthography affect vocabulary by children with low oral language levels. The investigators will use a 2 x 2 within-subjects factorial design where every participant receives the treatment. This 12-week study aims to improve vocabulary learning efficiency for children with low oral language levels. The study's findings will uniquely contribute to the field in that this is the first research study using real words instead of nonwords while combining word learning research with vocabulary learning.
Read the detailed description
The investigators are proposing a vocabulary intervention that analyzes word sounds and sound segments. This analysis offers valuable insights into how children at risk for specific learning disabilities, such as dyslexia, DLD or speech and language impairments, learn words differently from typically developing children.
- Conditions
- DLD
- Being tested
- VOCAB +
- Keywords
- developmental language disorder, vocabulary, intervention, bilingual, reading, phonotactic probability, word learning,
- Medical subject headings
- Language Development Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
VOCAB +Behavioural
The purpose of the study is to investigate how phonotactic probability and orthography effect vocabulary learning by children with low oral language levels. We will be using a 2 x 2 within-subjects factorial design where every participant serves as their own control. This 12-week study aims to improve the efficiency of vocabulary learning for children with low oral language levels.
The four interventions that are all participants will be exposed to are the following: high pp words with orthography; high pp words without orthography; low pp words with orthography; low pp words without orthography.
| Study group | Role | What they receive |
|---|---|---|
| Single group Assignment | Other | There are no subgroups in this study. All participants will receive the intervention. Receives: Behavioral: VOCAB + |
What is being measured
The primary outcome is the main question the study is designed to answer.
1. Vocabulary Production 2. Vocabulary Recognition 3. Vocabulary Comprehension 4. Spelling
- Production Number of correctly produced target words (range 0-32), measured using a picture-naming task, scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12)
- Recognition Number of correctly identified target words from a 4-choice array (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12)
- Comprehension Number of correctly selected target images from a 4-option array (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12)
- Spelling Number of correctly spelled target words (range 0-32), measured using a dictated spelling task, scored as correct (1) or incorrect (0), and reported as percentage correct.
Time Frame Posttest (Weeks 11-12)
Measured: up to 12 weeks
Secondary outcomes (2)
1. Learning Change Vocabulary Production 2. Learning Change Vocabulary Recognition 3. Learning Change Vocabulary Comprehension 4. Learning Change Vocabulary Spelling
- Production Change in the number of correctly produced target words (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct, measured at baseline and posttest. Time Frame Baseline (Weeks 1-2) to Posttest (Weeks 11-12)
- Recognition Change in the number of correctly identified target words (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct, measured at baseline and posttest. Time Frame Baseline (Weeks 1-2) to Posttest (Weeks 11-12)
- Comprehension Change in the number of correctly selected target images (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct, measured at baseline and posttest. Time Frame Baseline (Weeks 1-2) to Posttest (Weeks 11-12)
- Spelling Description Change in the number of correctly spelled target words (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct, measured at baseline and posttest.(Weeks 1-2) to Posttest
Measured: up to 12 weeks
1. Daily Vocabulary Production 2. Daily Vocabulary Recognition 3. Daily Vocabulary Comprehension 4.Daily Vocabulary Spelling
- Production Number of correctly produced target words per session (range 0-4), measured using a picture-naming task, scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Four times per week during the intervention period (Weeks 3-10)
- Recognition Number of correctly identified target words per session from a 4-choice array (range 0-4), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Four times per week during the intervention period (Weeks 3-10)
- Comprehension Number of correctly selected target images per session from a 4-option array (range 0-4), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Four times per week during the intervention period (Weeks 3-10)
- Spelling Number of correctly spelled target words per session (range 0-4), scored as correct (1) or incorrect (0), and reported as percentage correct.
Time Frame four times per week during the intervention
Measured: Weeks 3-10
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Apr 2025
- Study start3 Feb 2025
- Primary completion25 Apr 2025
- Study completion25 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for DLDStudies of the same condition, open and under way.
- More trials run by Arizona State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Within subject single group assignment
- Masking
- None (open label)
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- Arizona State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mariana Silva, Arizona State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06935851
- Sponsor's protocol ID
- STUDY00020728
- Acronym
- VOCAB+
- Status last verified
- Feb 2026
- First submitted
- 17 Dec 2024
- Last updated
- 18 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: * Study Protocol * Statistical Analysis Plan (SAP) * Informed Consent Form * Clinical Study Report
Study at a glance
From the registry record, last updated by the sponsor on 18 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Phonotactic Probability and Orthography on Vocabulary Learning
- ClinicalTrials.gov ID
- NCT06935851
- Acronym / sponsor ID
- VOCAB+ / STUDY00020728
- Conditions
- DLD
- Keywords
- developmental language disorder, vocabulary, intervention, bilingual, reading, phonotactic probability, word learning,
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 23 participants (actual)
- Lead sponsor
- Arizona State UniversityUniversity, hospital or other
- Study start
- 3 Feb 2025 (actual)
- Primary completion
- 25 Apr 2025 (actual)
- Study completion
- 25 Apr 2025 (actual)
- First posted
- 20 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the study is to investigate how phonotactic probability) and orthography affect vocabulary by children with low oral language levels. The investigators will use a 2 x 2 within-subjects factorial design where every participant receives the treatment. This 12-week study aims to improve vocabulary learning efficiency for children with low oral language levels. The study's findings will uniquely contribute to the field in that this is the first research study using real words instead of nonwords while combining word learning research with vocabulary learning.
Detailed description
The investigators are proposing a vocabulary intervention that analyzes word sounds and sound segments. This analysis offers valuable insights into how children at risk for specific learning disabilities, such as dyslexia, DLD or speech and language impairments, learn words differently from typically developing children.
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Within subject single group assignment
| Arm | Type | Receives |
|---|---|---|
| Single group Assignment | Other | Behavioral: VOCAB +There are no subgroups in this study. All participants will receive the intervention. |
Who may qualify
- Ages
- 8 to 9 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (1 listed)
- Enrolled in or just completed third grade.
Key exclusion criteria (1 listed)
- Any diagnosis of sensory impairments A diagnosis of autism or traumatic brain injury
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| VOCAB +The purpose of the study is to investigate how phonotactic probability and orthography effect vocabulary learning by children with low oral language levels. We will be using a 2 x 2 within-subjects factorial design where every participant serves as their own control. This 12-week study aims to improve the efficiency of vocabulary learning for children with low oral language levels. The four interventions that are all participants will be exposed to are the following: high pp words with orthography; high pp words without orthography; low pp words with orthography; low pp words without orthography. | Behavioural | Single group Assignment |
Primary outcome
1. Vocabulary Production 2. Vocabulary Recognition 3. Vocabulary Comprehension 4. Spelling
Time frame: up to 12 weeks
1. Production Number of correctly produced target words (range 0-32), measured using a picture-naming task, scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12) 2. Recognition Number of correctly identified target words from a 4-choice array (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12) 3. Comprehension Number of correctly selected target images from a 4-option array (range 0-32), scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12) 4. Spelling Number of correctly spelled target words (range 0-32), measured using a dictated spelling task, scored as correct (1) or incorrect (0), and reported as percentage correct. Time Frame Posttest (Weeks 11-12)
2 secondary outcomes
1. Learning Change Vocabulary Production 2. Learning Change Vocabulary Recognition 3. Learning Change Vocabulary Comprehension 4. Learning Change Vocabulary Spelling
Time frame: up to 12 weeks
1. Daily Vocabulary Production 2. Daily Vocabulary Recognition 3. Daily Vocabulary Comprehension 4.Daily Vocabulary Spelling
Time frame: Weeks 3-10
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 May 2026.
- Individual participant dataSharing planned: Yes. * Study Protocol * Statistical Analysis Plan (SAP) * Informed Consent Form * Clinical Study Report
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing VOCAB + in people with DLD, run by Arizona State University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
1. Vocabulary Production 2. Vocabulary Recognition 3. Vocabulary Comprehension 4. Spelling (time frame: up to 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 May 2026; AzTrials last refreshed its copy on 7 Nov 2026.