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NCT Number: NCT06935851

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.

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Key information

Conditions

DLD Communication Disorders Language Development Disorders Language Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

8 year–9 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Osborn District School Encanto

Phoenix, Arizona, 85013, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Enrolled in or just completed third grade.

Exclusion criteria

Any diagnosis of sensory impairments A diagnosis of autism or traumatic brain injury

Treatment and study plan

VOCAB +

Behavioral

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.

Primary outcomes

  1. 1. Vocabulary Production 2. Vocabulary Recognition 3. Vocabulary Comprehension 4. Spelling

    Time frame: up to 12 weeks

    • 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)

Secondary outcomes

  1. 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

    • 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

  2. 1. Daily Vocabulary Production 2. Daily Vocabulary Recognition 3. Daily Vocabulary Comprehension 4.Daily Vocabulary Spelling

    Time frame: Weeks 3-10

    • 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

Sponsors and collaborators

Lead sponsor

Arizona State University

Other

Registry information

Official study title

The Effect of Phonotactic Probability and Orthography on Vocabulary Learning

Acronym: VOCAB+

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Apr 20, 2025
Registry last updated
May 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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