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Abstract Visual-world eye-tracking has long been a useful tool for measuring young children’s real-time interpretation of words and sentences. Recently, researchers have extended this method to virtual platforms to reduce equipment costs and recruit more diverse participants. However, there is currently limited guidance on best practices, which require individual researchers to invent their own methodologies and may prevent broader adoption. Here, we present three broad approaches for implementing nine remote visual-world eye-tracking studies, and show that this method is highly feasible for assessing fine-grained language processing across populations of varying ages, clinical statuses, and socioeconomic status backgrounds. We outline strategic methods for conducting this research effectively, including strategies for experimental design, data collection, and data analysis given the variable conditions outside of a lab setting. We adopt four criteria for evaluating success for this method: 1) Minimal subject attrition relative to in-person studies, 2) Minimal track loss relative to conventional eye-tracking, 3) Conceptual replication of previous findings, and 4) Evidence of broadening participation. These case studies provide a thorough guide to future researchers looking to conduct remote eye-tracking research with developmental populations. Ultimately, we conclude that visual-world eye-tracking using internet-based methods is feasible for research with young children and may provide a relatively inexpensive option that can reach a broader, more diverse set of participants. 

Characterizing DNA methylation patterns is important for addressing key questions in evolutionary biology, development, geroscience, and medical genomics. While costs are decreasing, whole-genome DNA methylation profiling remains prohibitively expensive for most population-scale studies, creating a need for cost-effective, reduced representation approaches (i.e., assays that rely on microarrays, enzyme digests, or sequence capture to target a subset of the genome). Most common whole genome and reduced representation techniques rely on bisulfite conversion, which can damage DNA resulting in DNA loss and sequencing biases. Enzymatic methyl sequencing (EM-seq) was recently proposed to overcome these issues, but thorough benchmarking of EM-seq combined with cost-effective, reduced representation strategies is currently lacking. To address this gap, we optimized the Targeted Methylation Sequencing protocol (TMS)—which profiles ~4 million CpG sites—for miniaturization, flexibility, and multispecies use. First, we tested modifications to increase throughput and reduce cost, including increasing multiplexing, decreasing DNA input, and using enzymatic rather than mechanical fragmentation to prepare DNA. Second, we compared our optimized TMS protocol to commonly used techniques, specifically the Infinium MethylationEPIC BeadChip (n = 55 paired samples) and whole genome bisulfite sequencing (n = 6 paired samples). In both cases, we found strong agreement between technologies (R² = 0.97 and 0.99, respectively). Third, we tested the optimized TMS protocol in three non-human primate species (rhesus macaques, geladas, and capuchins). We captured a high percentage (mean = 77.1%) of targeted CpG sites and produced methylation level estimates that agreed with those generated from reduced representation bisulfite sequencing (R² = 0.98). Finally, we confirmed that estimates of 1) epigenetic age and 2) tissue-specific DNA methylation patterns are strongly recapitulated using data generated from TMS versus other technologies. Altogether, our optimized TMS protocol will enable cost-effective, population-scale studies of genome-wide DNA methylation levels across human and non-human primate species. 

Abstract Research has suggested that children who speak African American English (AAE) have difficulty using features produced in Mainstream American English (MAE) but not AAE, to comprehend sentences in MAE. However, past studies mainly examined dialect features, such as verbal -s , that are produced as final consonants with shorter durations when produced in conversation which impacts their phonetic saliency. Therefore, it is unclear if previous results are due to the phonetic saliency of the feature or how AAE speakers process MAE dialect features more generally. This study evaluated if there were group differences in how AAE- and MAE-speaking children used the auxiliary verbs was and were, a dialect feature with increased phonetic saliency but produced differently between the dialects, to interpret sentences in MAE. Participants aged 6, 5–10, and 0 years, who spoke MAE or AAE, completed the DELV-ST, a vocabulary measure (PVT), and a sentence comprehension task. In the sentence comprehension task, participants heard sentences in MAE that had either unambiguous or ambiguous subjects. Sentences with ambiguous subjects were used to evaluate group differences in sentence comprehension. AAE-speaking children were less likely than MAE-speaking children to use the auxiliary verbs was and were to interpret sentences in MAE. Furthermore, dialect density was predictive of Black participant’s sensitivity to the auxiliary verb. This finding is consistent with how the auxiliary verb is produced between the two dialects: was is used to mark both singular and plural subjects in AAE, while MAE uses was for singular and were for plural subjects. This study demonstrated that even when the dialect feature is more phonetically salient, differences between how verb morphology is produced in AAE and MAE impact how AAE-speaking children comprehend MAE sentences. 

Purpose: Stuttering-like disfluencies (SLDs) and typical disfluencies (TDs) are both more likely to occur as utterance length increases. However, longer and shorter utterances differ by more than the number of morphemes: They may also serve different communicative functions or describe different ideas. Decontextualized language, or language that describes events and concepts outside of the “here and now,” is associated with longer utterances. Prior work has shown that language samples taken in decontextualized contexts contain more disfluencies, but averaging across an entire language sample creates a confound between utterance length and decontextualization as contributors to stuttering. We coded individual utterances from naturalistic play samples to test the hypothesis that decontextualized language leads to increased disfluencies above and beyond the effects of utterance length. Method: We used archival transcripts of language samples from 15 preschool children who stutter (CWS) and 15 age- and sex-matched children who do not stutter (CWNS). Utterances were coded as either contextualized or decontextualized, and we used mixed-effects logistic regression to investigate the impact of utterance length and decontextualization on SLDs and TDs. Results: CWS were more likely to stutter when producing decontextualized utterances, even when controlling for utterance length. An interaction between decontextualization and utterance length indicated that the effect of decontextualization was greatest for shorter utterances. TDs increased in decontextualized utterances when controlling for utterance length for both CWS and CWNS. The effect of decontextualization on TDs did not differ statistically between the two groups. Conclusions: The increased working memory demands associated with decontextualized language contribute to increased language planning effort. This leads to increased TD in CWS and CWNS. Under a multifactorial dynamic model of stuttering, the increased language demands may also contribute to increased stuttering in CWS due to instabilities in their speech motor systems. 

Purpose:Language sample analysis (LSA) is a commonly recommended method of assessment for bilingual children. This systematic review and meta-analysis provides a comprehensive overview of the literature on the use of LSA to differentiate between developmental language disorder (DLD) and typical language (TL) in bilingual children. Method:We conducted a search of several large electronic databases along with forward and backward searches and applied abstract and full-text screening procedures to identify all relevant studies. We then estimated standardized mean differences, representing the ability of LSA to differentiate between DLD and TL, using multilevel model and subgroup and moderator analyses to identify characteristics of LSA that may be associated with differences in effect size magnitude. We conducted assessments of publication bias and risk of bias by examining quality indicators for each study. Results:The search yielded 35 articles that met the inclusion criteria. Participants ranged in age from 2;0 (years;months) to 11;9, with over 40 languages represented. Across studies, the pooled standardized mean difference indicated that children with DLD performed 0.78SDlower on LSA measures than those with TL. Measures of morphosyntactic accuracy exhibited the largest pooled effect size. Elicitation method, language of task, and age were not associated with differences in effect size. Discussion:Results of this study provide evidence of the clinical utility of LSA in differentiating between DLD and TL in bilingual children. Further research is needed to examine classification accuracy as well as task characteristics that may improve its diagnostic utility. 

ABSTRACT Characterizing DNA methylation patterns is important for addressing key questions in evolutionary biology, geroscience, and medical genomics. While costs are decreasing, whole-genome DNA methylation profiling remains prohibitively expensive for most population-scale studies, creating a need for cost-effective, reduced representation approaches (i.e., assays that rely on microarrays, enzyme digests, or sequence capture to target a subset of the genome). Most common whole genome and reduced representation techniques rely on bisulfite conversion, which can damage DNA resulting in DNA loss and sequencing biases. Enzymatic methyl sequencing (EM-seq) was recently proposed to overcome these issues, but thorough benchmarking of EM-seq combined with cost-effective, reduced representation strategies has not yet been performed. To do so, we optimized Targeted Methylation Sequencing protocol (TMS)—which profiles ∼4 million CpG sites—for miniaturization, flexibility, and multispecies use at a cost of ∼$80. First, we tested modifications to increase throughput and reduce cost, including increasing multiplexing, decreasing DNA input, and using enzymatic rather than mechanical fragmentation to prepare DNA. Second, we compared our optimized TMS protocol to commonly used techniques, specifically the Infinium MethylationEPIC BeadChip (n=55 paired samples) and whole genome bisulfite sequencing (n=6 paired samples). In both cases, we found strong agreement between technologies (R² = 0.97 and 0.99, respectively). Third, we tested the optimized TMS protocol in three non-human primate species (rhesus macaques, geladas, and capuchins). We captured a high percentage (mean=77.1%) of targeted CpG sites and produced methylation level estimates that agreed with those generated from reduced representation bisulfite sequencing (R² = 0.98). Finally, we applied our protocol to profile age-associated DNA methylation variation in two subsistence-level populations—the Tsimane of lowland Bolivia and the Orang Asli of Peninsular Malaysia—and found age-methylation patterns that were strikingly similar to those reported in high income cohorts, despite known differences in age-health relationships between lifestyle contexts. Altogether, our optimized TMS protocol will enable cost-effective, population-scale studies of genome-wide DNA methylation levels across human and non-human primate species. 

Socioeconomic status (SES) differences in language development are ubiquitous, but existing research has yet to wrestle with how language gaps reflect ( a) differences in relevant concepts for communication, ( b) comprehension strategies to access meanings, and ( c) production practices that express social identity. In child-directed input, parents use verbs to describe similar concepts across SES, and the largest gaps emerge when frequent meanings are being conveyed. During comprehension, children acquire infrequent aspects of grammar across SES but differ in context-specific strategies for interpreting likely meanings. In production, children are sensitive to sociolinguistic implications and adopt context-specific strategies to signal social identity. This suggests that language is a flexible medium for communicating thoughts and that SES effects signal latent differences in meanings and identities across social classes. Whether language gaps contribute to achievement gaps may depend on the extent to which learning and communication draw on these meanings and value these identities. 

As members of the editorial team at Language Acquisition, we read Kidd and Garcia’s target article with enthusiasm. In our commentary, we outline some specific ideas for how journals can help to alleviate the issues raised by Kidd and Garcia, some of which are in progress or in place at Language Acquisition, and some of which we hope to undertake alongside other journals in the field. We focus on concrete steps, acknowledging that systemic changes, too, will be required to ensure that our science reflects the diversity of languages learned.