Open research questions in Language Development and Disorders

What the literature leaves open

• Stockman, I. J. (2010). A review of developmental and applied language research on African American children: From a def- icit differences. Language, Speech, and Hearing Services in Schools, 41(1), 23–38. https://doi.org/10.1044/0161-1461(2009/08-0086) Storkel, H. L., Komesidou, R., Pezold, M. J., Pitt, A. R., Fleming, K. K., & Romine, R. S. (2019). The impact of dose and dose frequency on word learning by kindergarten children with language disorder during interactive book developmental Reading. Language, Speech, and Hearing Services in Schools, https://doi.org/10.1044/2019_ LSHSS-VOIA-18-0131 518–539. 50(4), McGregor et al. 27 Storkel, H. L., Voelmle, K., Fierro, V., Flake, K., Fleming, K. K., & Romine, R. S. (2017). Interactive book reading to accelerate word learning by kindergarten children with specific language impairment: Identifying an adequate intensity and variation in treatment response. Language, Speech, and Hearing Services in Schools, 48(1), 16–30. https://doi.org/10.1044/2016_ LSHSS-16-0014 Trueswell, J. C., Medina, T. N., Hafri, A., & Gleitman, L. R. (2013). Propose but verify: Fast mapping meets cross- situational word learning. Cognitive Psychology, 66(1), 126– 156. https://doi.org/10.1016/j.cogpsych.2012.10.001 Tsang, T., Atagi, N., & Johnson, S. P. (2018). Selective attention to the mouth is associated with expressive language skills in monolingual and bilingual infants. Journal of Experimental Child Psychology, 169, 93–109. https://doi.org/10.1016/j. jecp.2018.01.002 Ukoumunne, O. C., Wake, M., Carlin, J., Bavin, E. L., Lum, J., & Skeat, J., …, & Reilly, S. (2012). Profiles of language develop- ment in pre-school children: A longitudinal latent class analysis of data from the early language in Victoria study. Child: Care, Health and Development, 38(3), 341–349. https://doi.org/10. 1111/j.1365-2214.2011.01234.x Ukrainetz, T. A. (2024). The foundations of language intervention: Reasoning and research. In T. A. Ukrainetz (Ed.), School-age language intervention-second edition (pp. 43–72). Pro-Ed. Valiante, A. G., Barr, R. G., Zelazo, P. R., Papageorgiou, A. N., & Young, S. N. (2006). A typical feeding enhances memory for spoken words newborns. Pediatrics, 117(3), e476–e486. https://doi.org/10.1542/peds. 2004-2859 3-day-old healthy 2-to in van Berkel-van Hoof, L., Hermans, D., Knoors, H., & Verhoeven, L. (2019). Effects of signs on word learning by children with developmental Speech, Language, and Hearing Research, 62(6), 1798–1812. https:// doi.org/10.1044/2019_JSLHR-L-18-0275 language disorder.

  Word Learning Ability Varies Across Contexts and Time: A Longitudinal Study of Primary School Children with Developmental Language Disorder · 2026 · DOI

• A second limitation of the current study is that Benito’s correct responding during probes of English relations in the No IF condition increased, despite these targets never being presented.

  Using Instructive Feedback to Expand Second Language of Children with Autism Spectrum Disorder · 2026 · DOI

• This study is particularly valuable as it addresses a significantly underresearched population. By providing insight into their syntactic abilities in Croatian, this study helps fill a critical gap in the literature and contributes to a better understanding of language development in underrepresented bilingual groups.

  Syntactic Complexity of L2 Story Production in Minority Children with Mild Intellectual Disability: Quantitative and Qualitative Analysis · 2026 · DOI

• The current study has certain limitations that should be considered. First, it focused only on Chinese-English bilingual children from Grades 2, 5, and 8 in Hong Kong. This raises questions about the generalizability of the findings to bilinguals in other grade levels or those who speak other languages. Therefore, future research should extend the current study by including a broader range of bilingual populations with different language combinations and grade levels. Second, the cross-sectional design captures concurrent associations and cannot establish causal transfer between mor- phological awareness and reading comprehension. Directional effects should be tested in longitudinal designs that model stability and reciprocal influences over time. Third, the Chinese reading comprehension task, which was directly translated from the English task, yielded relatively low internal consistency. Future studies should develop tasks tailored for Chinese-speaking children. Fourth, the testing format dif- fered for upper and lower graders, which was designed taking into account varia- tions in their language and reading proficiency. It is crucial for future research to explore whether the testing format has any impact on task performance. Finally, our study included children with varying levels of reading comprehension. Future studies can categorize participants into good and poor comprehenders to investigate the role of morphological awareness in bilingual children with diverse reading levels. Work with monolinguals indicates that morphological awareness is associated with specific reading comprehension difficulties (Tong et al., 2011).

  Within- and cross-language pathways from morphological awareness to reading comprehension in Chinese-English bilingual children · 2026 · DOI

• In summary, existing CDI-based longitudinal research in neurodevelopmental and genetic con- ditions remains sparse and fragmented, falling short of delineating condition-specific develop- mental profiles, which is a long-standing aim of developmental clinical research.

  Longitudinal tracking of vocabulary development in children with neurodevelopmental and genetic disorders using Communicative Development Inventories (CDIs) · 2026 · DOI

• However, it remains unclear what factors uniquely drive the emergence and continued development of the VWFA, or more broadly shaping category selectivity across the VTC.

  Literacy acquisition and functional connectivity drive the emergence and continued development of the VWFA · 2026 · DOI

• A possible explanation may lie in the complexity of assessing ToM as a construct, as crucial aspects of its development and underlying mechanisms are still poorly understood (Rakoczy, 2022).

  Predictors of resilience in deaf and hard of hearing adolescents and adolescents with developmental language disorders · 2026 · DOI

• Further, teachers and other professionals frequently rely on internet searches to identify ways to support students with DLD in the classroom, yet the quality and evidence of these online sources remain unclear.

  Effective Whole Class Oral Language Interventions and Strategies for Students with Developmental Language Disorder: A Systematic Review · 2026 · DOI

• We hope that these studies will stimulate further research into the mechanisms, contexts, and trajectories of discourse development beyond early childhood, and so contribute to a more comprehensive theory of how language users build sophisticated, context-sensitive, and socially meaningful communicative competence across the lifespan.

  Editorial: Interacting factors in the development of discourse practices from childhood to adulthood · 2026 · DOI

• Future research should examine larger, longitudinal, and multimodal datasets to validate these developmental patterns, explore L1-L2 interactions in L3 acquisition, and triangulate corpus-based findings with qualitative analyses to confirm the cognitive sources of observed interference.

  L2 English interference in Chinese learners of L3 Portuguese: a corpus-based analysis of transfer-induced errors · 2026 · DOI

• This review has li⁠mitations. The inclusion o⁠f only English-language pub⁠lications may introdu⁠ce cultur⁠al an⁠d linguistic bias. Sign⁠ificant heterogeneity in operational definitions precluded a metaanalysis. Furt⁠hermore, the underrepresentation of⁠ non-Western contexts limits the generalizability of the findings. Future research shou⁠ld priorit⁠ize: (1) longit⁠udinal neuroimaging studies to track neuroplastic changes in b⁠ilingual development; (2) more studies in under-represented, non-Western multilingual contexts; an⁠d (3) rigorous intervention trials to evaluate the efficacy of speci⁠fic s upport strategies,⁠ such⁠ as parent-coachi⁠ng models or different biling⁠ual education programs.

  Early foreign language exposure and its dual effects on cognitive development and language competence in childhood · 2026 · DOI

• Several limitations qualify our conclusions. First, our sample size limits statistical power for detecting community differences and examining individual difference predictors, and the two communities differed along multiple dimensions beyond language, preventing clear causal attribution. Our 20-minute recordings, while capturing natural interaction, are likely more representative of peak moments of daily interaction than other moments in children's day. Collecting and coding more data will be time consuming, as reliable automated tools for detecting language switches are still in early stages of development and have not yet reached high levels of reliability. However, data of this scale are a necessary step toward a comprehensive and realistic picture of bilingual input. Second, we focused on within- and across-speaker switches, but future work should examine other dimensions of switching, including whether switches occur within or between sentences (e.g., Bail et al., 2015; Kremin et al., 2022), the directionality of switches relative to children's language dominance (Potter et al., 2019), and the temporal patterning of switches throughout the day (e.g., Cychosz et al., 2025b). Future research should also explore how characteristics of the speakers in toddlers' environments, including their language proficiency, attitudes toward bilingualism, and social networks beyond the household (e.g., childcare providers, teachers), influence switching patterns and bilingual development (e.g., Okocha et al., 2024). 36 Finally, our findings also raise important questions about ecological validity in bilingual research. Most experimental studies test within-speaker switches, yet our data reveal that across-speaker switches are more common in naturalistic multi-party interactions. Understanding whether and how these different types of switches present distinct processing challenges remains a critical direction for future work. Additionally, while our results highlight substantial variability in switching exposure across families, they also reveal potential sources of predictability, particularly the stability of individual caregivers' switching patterns, that may scaffold bilingual learning in ways that parallel how routines and predictable contexts support monolingual development (Roy et al., 2015; Tamis-LeMonda et al., 2019).

  Social and Community Influences on Language Switching in Bilingual Toddlers’ Everyday Input · 2026 · DOI

• Studies on functional elements in infant processing (Höhle et al. 2004, Kim & Sundara 2021) demonstrate sensitivity to morphology and determiners by 6-19 months, but the excerpt does not indicate whether functional morphemes specifically signal filler-gap dependency structure in child-directed speech. Corpus-based analysis of morphosyntactic marking of movement dependencies in naturalistic input to children is needed.

  Mind the gap: Learning the surface forms of movement dependencies · 2026 · DOI

• The paper references work on filtering input for grammatical variability (Maitra & Perkins 2023) and statistical learning of phonetic categories (McMurray et al. 2009), but does not specify computational models that simulate how learners extract and weight surface form cues (e.g., morphological agreement, word order patterns, intonational boundaries) when learning constrained movement dependencies from naturalistic corpora.

  Mind the gap: Learning the surface forms of movement dependencies · 2026 · DOI

• The cited work on syntactic bootstrapping (Jin & Fisher 2014, Lidz et al. 2017) focuses on incremental parsing in verb learning, but does not explicitly test whether children use acoustic-prosodic surface cues versus purely structural cues to identify movement dependencies in naturalistic speech input. Controlled experiments manipulating prosodic marking of filler-gap boundaries are needed.

  Mind the gap: Learning the surface forms of movement dependencies · 2026 · DOI

• Existing studies cited (Hirzel et al. 2020, Höhle et al. 2006) examine filler-gap dependency processing in 19-month-olds, but there is no specification of whether younger infants (12-15 months) or older children (24+ months) progressively refine their representation of discontinuous verbal dependencies. The developmental trajectory of learning surface form cues for movement dependencies across a wider age range needs empirical characterization.

  Mind the gap: Learning the surface forms of movement dependencies · 2026 · DOI

• The paper examines filler-gap dependencies in infants and children, but the excerpt does not specify whether movement dependencies have been tested across typologically diverse languages beyond English, German, and Mandarin. Future work should investigate whether children learning languages with different word order patterns (SOV, VOS, or ergative-absolutive systems) show similar developmental trajectories in parsing surface forms of movement dependencies.

  Mind the gap: Learning the surface forms of movement dependencies · 2026 · DOI

• The relationship between media language structure (TV shows and movies) and children's classifier learning remains underexplored. While the paper positions media language as intermediate between child-directed speech and books, experimental studies are needed to quantify how screen-based classifier input affects children's classifier acquisition relative to other modalities.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• The claim that classifiers should be treated as continuous distributions similar to English adjectives requires experimental psycholinguistic evidence demonstrating that children process classifiers with similar gradient effects as they do for pre-nominal modifiers. The theoretical reconceptualization away from the binary 个(ge4)/specific classifier distinction needs empirical support from language processing studies.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• Classifier distribution patterns need to be examined across specific contexts within each modality, such as how classifier entropy and specificity vary with successive noun mentions in children's books versus real-time child-directed speech interactions. Current aggregated corpus analyses do not capture these context-dependent distributional variations within modalities.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• Age-related differences in classifier use patterns require systematic investigation with larger datasets for each age group. Current exploratory analyses lack sufficient child-directed speech data per age group to reliably determine whether classifier diversity increases developmentally in spoken input (as found in books) or remains constant across childhood stages.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• The CHILDES corpus-based child-directed speech dataset is limited to indoor contexts (home, research settings) and play routines; it lacks representation of outdoor experiences (parks, trips) where caregivers may use a broader range of classifier types and phrases. A more comprehensive child-directed speech corpus capturing diverse contextual settings is needed to accurately estimate the full range of classifiers children encounter.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• Experimental validation is needed to establish causal relationships between classifier exposure frequency in different modalities (child-directed speech, children's books, media) and children's actual learning and processing of Chinese classifiers and classifier–noun mappings. Current corpus analysis cannot determine how differences in reading frequency directly affect classifier acquisition outcomes.

  Learning from the Input: A Corpus-Based Investigation of Chinese Classifiers in Children’s Books and Child-Directed Speech · 2026 · DOI

• Future research should also consider other dimensions of syllabic production and include complementary indicators, such as Whole Word Match or Percentage of Consonants Correct, to expand multidimensional analysis of PPD in Chilean Spanish.

  Development of word and syllable structure in Chilean children with typical and protracted phonological development · 2026 · DOI

• Stress was not included as an independent factor in the present analyses because the PFE was not designed to manipulate stress position systematically, and because the strong predominance of paroxytone patterns in Spanish limits its variability as a predictor.

  Development of word and syllable structure in Chilean children with typical and protracted phonological development · 2026 · DOI

Most-cited papers in Language Development and Disorders

• Early vocabulary growth: Relation to language input and gender. · Developmental Psychology · 1991 · 1,155 citations
• Neurocognitive correlates of socioeconomic status in kindergarten children · Developmental Science · 2004 · 698 citations
• The kindergarten-path effect: studying on-line sentence processing in young children · Cognition · 1999 · 474 citations
• Relations Among Speech, Language, and Reading Disorders · Annual Review of Psychology · 2008 · 429 citations
• What counts in the development of young children's number knowledge? · Developmental Psychology · 2010 · 371 citations
• Does input influence uptake? Links between maternal talk, processing speed and vocabulary size in Spanish‐learning children · Developmental Science · 2008 · 363 citations
• Emotional and behavioural outcomes later in childhood and adolescence for children with specific language impairments: meta‐analyses of controlled prospective studies · Journal of Child Psychology and Psychiatry · 2012 · 359 citations
• Oral language deficits in familial dyslexia: A meta-analysis and review. · Psychological Bulletin · 2016 · 358 citations
• Levels of bilingualism and levels of linguistic awareness. · Developmental Psychology · 1988 · 332 citations
• What did Simon say? Revisiting the bilingual advantage · Developmental Science · 2007 · 325 citations

Most recent work

• Development of word and syllable structure in Chilean children with typical and protracted phonological development · Frontiers in Psychology · 2026
• The Role of Language Aptitude in Child Second Language Learning: A Meta-analysis · Educational Psychology Review · 2026
• Representations of Nonlocal Syntactic Dependencies Feed Verb Learning in Infancy · Developmental Science · 2026
• Social and Community Influences on Language Switching in Bilingual Toddlers’ Everyday Input · 2026
• Discovering regularity and mechanisms of word sense acquisition in childhood · Proceedings of the National Academy of Sciences · 2026
• Effects of cognitive flexibility on children’s Pinyin identification: Selective modulation across phonological interference conditions · Journal of Early Childhood Research · 2026
• Language mixing in young multilingual children and its correlates: a systematic review · Developmental Review · 2026
• Early Word Learning in Context: A Review of the Literature · Infant and Child Development · 2026
• Investigating the predictors of academic language competences in primary school children: A machine learning approach · Preschool and Primary Education · 2026
• How do differences in bilingual input affect vocabulary development of a minority language? The relationship between the type of bilingual exposure and early vocabulary acquisition · International Journal of Bilingualism · 2026

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