Retrieval-Based Word Learning in Developmental Language Disorder During Book Reading II

Developmental Language Disorder (DLD) affects language learning in an estimated 7% of children. Although much of the research literature has emphasized difficulties learning grammar, children with DLD also have major deficits in vocabulary. In recent work, the investigators have been examining the benefit of retrieval practice to enhance word learning and retention in preschoolers with DLD. The rationale behind this work is grounded in the growing literature in the field of cognitive psychology which shows that repeated practice in retrieving information results in greater long-term retention than continuous study of that information without opportunities for retrieval. In addition, retrieval practice that occurs after a delay-or "spacing" between study of a word and subsequent recall attempts-can lead to stronger effects.

The investigators have explored the benefits of retrieval practice for preschoolers with DLD and with typical language development (TD), showing that recall and retention for novel words (nouns, adjectives, verbs) were greater when learned using repeated spaced retrieval (RSR) than when learned using repeated study only. Despite benefiting from RSR, children with DLD still showed lower levels of recall than children with TD.

In the investigators' immediately preceding study, the same words and retrieval schedules used in earlier studies were embedded into story contexts. Artist-illustrated stories incorporated illustrations of the unfamiliar plants and animals that served as referents of novel nouns. The findings of greater learning with RSR than with RS were replicated. However, in that study, the words were merely mentioned in the story, as objects that the characters happened to see along their journey. In this new study, the words to be learned are more tightly integrated into the story line, to more closely approximate the everyday shared book reading that occurs in homes, preschools, and clinics. Sixteen children with DLD will be recruited for this study along with 16 children with TD matched on chronological age. Using a within-subjects design, children will learn eight novel nouns, four embedded in each story. Along with each word form, children will learn a "meaning", that is, an additional piece of semantic information about the referent.

For words in the RSR condition, each novel word and meaning, paired with its referent, will be presented as part of the story. Immediately after hearing it, children will be asked to recall both form and meaning, and then will hear those repeated. All subsequent retrieval trials will occur after three other words have intervened since the last time the word appeared in a study trial. Novel words assigned to the comparison condition will simply be heard paired with their referent during the story at the same frequency as words in the RSR condition. Children will not be asked to recall the words in the comparison condition during the learning period. Stories will be presented twice, on two consecutive days. As written, children will hear the words the same number of times overall as in the investigator's previous studies, allowing evaluation of the benefits of the story format. Recall of the word forms and meanings will be tested after the story book reading on both the first and second days. One week later, the recall test will be re-administered and children will complete a three-alternative recognition test.

The investigators hypothesize that the findings will replicate the findings of their immediately preceding study, this time with the words integrated to a greater extent within the stories, thus more closely approximating the more typical shared book reading experienced by children. Specifically, the children will show greater recall for word forms and meanings in the RSR condition than those in the repeated study condition. Past studies have not consistently shown an advantage for recognition; therefore, we do not predict a difference for this particular measure. It is also expected that children with TD will remember more words overall than children with DLD. To the degree that the story format is more engaging for children, overall recall will be enhanced for both groups. Assuming that the results are replicated, it is hoped that the children's book reading format will prove amenable for use by teachers and speech-language pathologists who work with children with DLD.

• Retrieval-based word learning: Repeated Spaced Retrieval condition (Behavioral): Each child will learn 8 novel nouns referring to unfamiliar plants and animals ("nepp") and a related "meaning" ("a nepp likes rain") in the context of a story book. Four of the nouns will be will be learned using repeated spaced retrieval. In this condition, they will initially hear the information and be asked to retrieve it. Thereafter, they will be asked to retrieve it after hearing 3 intervening words. After each retrieval attempt, they will hear the target information again. This procedure will occur on two consecutive days.
• Retrieval-based word learning: Repeated Study condition (Behavioral): Each child will learn 8 novel nouns referring to unfamiliar plants and animals ("nepp") and a related "meaning" ("a nepp likes rain") in the context of a story book. Four of the nouns will be will be learned using repeated study trials only (with no retrieval practice). In this condition, they will simply hear the information (word \& meaning) as part of the story. This procedure will occur on two consecutive days.

Primary outcomes

• Word Form Recall Accuracy (Number of Words Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, 5 Mins. [5 minutes after end of first (Day 2) learning period]: Five minutes after second learning session, the child was asked to recall and say the word associated with each novel referent, learned under one of two conditions: a condition in which spaced retrieval trials occurred (RSR) and one in which there were no retrieval trials (RS). Each of the four verbs were tested twice, for a total of 8 recall items per condition.
• Word Form Recall Accuracy (Number of Words Correctly Recalled) in Repeated Spaced Retrieval (RSR) and Repeated Study (RS) Conditions, One Week [One week after end of learning period]: One week after second learning session, the child was asked to recall and say the word associated with each novel referent, learned under one of two conditions: a condition in which spaced retrieval trials occurred (RSR) and one in which there were no retrieval trials (RS). Each of the four verbs were tested twice, for a total of 8 recall items per condition.
• Word Meaning Recall Accuracy (Number of Semantic Associations Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, 5 Minutes [5 minutes after end of first (Day 2) learning period]: Five minutes after second day's learning session, the child was asked to recall and say the word associated with each novel referent, learned under one of two conditions: a condition in which spaced retrieval trials occurred (RSR) and one in which there were no retrieval trials (RS). Each of the four verbs were tested twice, for a total of 8 recall items per condition.
• Word Meaning Recall Accuracy (Number of Semantic Associations Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, One Week [One week after Day 2 learning period]: One week after second learning session, the child was asked to recall and say the semantic information associated with each novel referent, learned under one of two conditions: a condition in which spaced retrieval trials occurred (RSR) and one in which there were no retrieval trials (RS). Each of the four verbs were tested twice, for a total of 8 recall items per condition.
• Word Recognition (Number of Words Accurately Identified) in Repeated Spaced Retrieval (RSR) and Repeated Study (RS) Conditions. [One week after end of learning period]: Upon hearing a novel word, the child is asked to indicate (by pointing) which picture among 3 options is referred to; for words learned under the RSR and RS conditions.

Secondary outcomes

• Peabody Picture Vocabulary Test, Fifth Edition [Test completed at start of study]: The Peabody Picture Vocabulary is an individually administered, norm-reference test that assesses receptive vocabulary (ability to understand individual words) for children and adults ages 2 years 6 months to 90 years and older. Standard scores are derived from number correct. Standard scores can range from a minimum of 40 and 160. Standard scores between 85 and 115 (1 standard deviation above and below the mean of 100) are interpreted as reflecting receptive vocabulary levels expected for age. Scores below 85 are interpreted as reflecting receptive vocabulary levels below what is expected for age.Scores above 115 are interpreted as reflecting receptive vocabulary levels above what is expected for age.
• Years of Maternal Education [Information collected at start of study]: Educational attainment of child's mother in terms of years of education

Sex: All, ages: 48 Months to 71 Months, accepts healthy volunteers

Inclusion Criteria:

* a significant deficit in language ability (language test score below cutoff for best sensitivity/specificity) or documented age-appropriate language ability.
* normal hearing.
* no evidence of neurological damage or disease.
* scores on tests of nonverbal intelligence above the intellectual disability range
* not within Autistic range on Autism screening test
* native English speaker (can be bilingual)

Exclusion Criteria:

* failed hearing screening
* known neurological damage or disease
* scores on tests of nonverbal intelligence below the intellectual disability range (standard score less than 75)
* autism spectrum disorder
* non-native English speaker

Participant flow

Outcome results

• Word Form Recall Accuracy (Number of Words Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, 5 Mins. (Primary), Mean, number of words correctly recalled: Children With Developmental Language Disorder 3.71 +/- 0.54; Children With Typical Language Development 4.71 +/- 0.54 (p 0.004)
• Word Form Recall Accuracy (Number of Words Correctly Recalled) in Repeated Spaced Retrieval (RSR) and Repeated Study (RS) Conditions, One Week (Primary), Mean, number of words correctly recalled: Children With Developmental Language Disorder 3.50 +/- 0.57; Children With Typical Language Development 4.29 +/- 0.57 (p 0.04)
• Word Meaning Recall Accuracy (Number of Semantic Associations Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, 5 Minutes (Primary), Mean, number of meanings correctly recalled: Children With Developmental Language Disorder 7.07 +/- 0.25; Children With Typical Language Development 7.79 +/- 0.25 (p 0.008)
• Word Meaning Recall Accuracy (Number of Semantic Associations Correctly Recalled) in Repeated Spaced Retrieval and Repeated Study Conditions, One Week (Primary), Mean, number of meanings correctly recalled: Children With Developmental Language Disorder 7.00 +/- 0.31; Children With Typical Language Development 7.79 +/- 0.31 (p 0.00002)
• Word Recognition (Number of Words Accurately Identified) in Repeated Spaced Retrieval (RSR) and Repeated Study (RS) Conditions. (Primary), Mean, number or words correctly recognized: Children With Developmental Language Disorder 7.57 +/- 0.21; Children With Typical Language Development 7.64 +/- 0.21 (p 0.019)
• Peabody Picture Vocabulary Test, Fifth Edition (Secondary), Mean, score on a scale: Children With Developmental Language Disorder 103.64 +/- 12.80; Children With Typical Language Development 114.00 +/- 14.20 (p 0.053)
• Years of Maternal Education (Secondary), Mean, years: Children With Developmental Language Disorder 14.57 +/- 2.24; Children With Typical Language Development 17 +/- 1.24 (p 0.002)

Adverse events

Time frame: 4 weeks

• Study Protocol and Statistical Analysis Plan (PDF, 2025-02-24)
• Informed Consent Form (PDF, 2025-03-01)

• Laurence B. Leonard, PhD, Principal investigator, Purdue University

NIH grants: R01DC014708