Deciphering the Language in Our DNA and Leveraging the Discoveries Toward Improved Outcomes: Introduction to the Forum

Abstract

Purpose:

Investigating genetic influences on speech and language development is a fairly new field fueled by interprofessional collaborations among investigators trained in genomics, communication sciences and disorders, or, in rare cases, both. The 2024 Research Symposium, titled “Genetics in Communication Sciences and Disorders,” aimed to provide updates on cutting-edge research findings in disorders of speech sound production, speech fluency, spoken language, and written language. A second important goal was to make research methods and findings of genetics studies in speech and language disorders accessible to an audience with expertise in communication sciences and disorders. The articles in this forum are based on the symposium presentations.

Conclusion:

The authors trace the history of investigating genotype–phenotype associations in their areas of specialty and discuss how technological advances have fueled recent insights in large participant samples. In addition, we show how insights from genetic studies of spoken and written language can be leveraged toward novel interventions based on principles of precision medicine, namely personalized and proactive approaches, with the goal of improved outcomes. A disclaimer is that genetic changes reflect only one of many sources of influence on the human capacity of verbal communication; many others—for instance microbiomes and the physical, social, and cultural environments—should also be acknowledged.

The human brain consists of 86 billion neurons and counting (Goriely, 2025). The human genome contains 20,000 genes, give or take. The human capacity for language, both spoken and written, is undoubtably mediated by the brain and under genetic influence. The sheer complexities of our central and peripheral nervous systems on one side and the vast size of our genome and its functional interactions on the other would seem to make it impossible or at least massively daunting to discover how genes influence speech and language. Five speakers at the 2024 Research Symposium, titled “Genetics in Communication Sciences and Disorders,” not only shed bright beams of light into this seeming black box but also point out how knowledge of genotype–phenotype associations can be translated into clinical practice toward improved outcomes.

To contextualize this work, consider the differences between medical genetics and behavioral genetics. Journals in the field of medical genetics regularly report on genetic aspects of medical conditions such as cancer, diabetes, cardiac disease, musculoskeletal diseases, epilepsy, and blindness, to name a few. In the world of medical genetics, diseases, disorders, or syndromes are managed by medical health care providers, diagnosed using medical tools, and addressed with medical interventions such as pharmaceutical or surgical treatments. In contrast, the field of behavioral genetics focuses on behaviorally expressed traits, both typical and atypical, such as cognitive and verbal abilities, social behaviors, trust, altruism, substance use, anxiety, and aggression. Behavioral traits with clinical significance are often managed by clinical health-care providers; diagnosed using behavioral tools such as interviews, questionnaires, and standardized tests; and treated with behavioral interventions such as counseling, psychotherapy, or special education services. Investigations of genetic influences on speech and language development fall largely into the domain of behavior genetics (Peter et al., 2022, 2023).

The goals of the symposium included not only providing updates on cutting-edge research findings but also contributing to interprofessional accessibility among researchers and clinicians with expertise in communication sciences and disorders. As we and others have shown, practicing speech-language pathologists are aware of the relevance of genetics for their clinical practice but report limited to no training in that area (Peter et al., 2019; Tramontana et al., 2013). Similarly, we find that experts in molecular and medical genetics could benefit from deeper insights into communication sciences and disorders, because speech and language abilities represent a microcosm of genotype–phenotype associations that can inform clinical management (Bruce & Peter, 2022; Chenausky & Tager-Flusberg, 2022; Peter, 2023; Peter, Aggarwal, et al., 2025).

Fittingly, the curtain of this forum opens with a tutorial. Here, Simon E. Fisher, co-discoverer of the first human speech and language gene in 2001, traces the young history of how some key genotype–phenotype associations in the speech and language domains were discovered (Fisher, 2025). He first discusses how single genetic variants of large effect can cause severe speech sound disorders with associated language impairments, then moves to disorders of speech and language that arise from many genetic variants, each of small but cumulative effect. Recent technological advances fueled studies with large sample sizes that led to the discoveries of such additive genetic variants, truly an explosion of knowledge.

Barbara A. Lewis, Gabrielle J. Miller, Penelope Benchek, Catherine Stein, and Sudha K. Iyengar review insights and challenges from work in the Cleveland Family Speech and Reading Study spanning 25 years (Lewis et al., 2025). They address longitudinal aspects of speech and language phenotypes—for instance, the predictive relationship between early motor difficulties and subsequent speech/language difficulties in adolescence and adulthood. Insights include the surprising numbers of sporadic (i.e., not inherited) variants; challenges include the dearth of standardized measures for speech and language abilities throughout the lifespan.

Dillon G. Pruett, Alyssa C. Scartozzi, Hannah G. Polikowsky, Heather M. Highland, Doug M. Shaw, Lauren E. Petty, Alex S. Petty, Shelly Jo Kraft, and Jennifer E. Below review insights and challenges in identifying genetic causes for stuttering (Pruett et al., 2025). The team has amassed genotype and phenotype data in a large sample of individuals who stutter (International Stuttering Project) and leveraged other large-scale databases toward discovery of genes that influence speech fluency. Insights include newly discovered genes that disrupt speech fluency; challenges include the underspecification of stuttering phenotypes in medical records and the unanswered question of how genetic variants lead to the clinically observable traits, given that some key genes are expressed in various tissues besides the brain.

Pavel Dobrynin, Yi Zeng, Marina Norkina, Alina Fedorova, Anna Zhuk, and Elena L. Grigorenko review four decades of inquiry into the genetic bases of specific reading disability (Dobrynin et al., 2025). Their chosen phenotype differs from the phenotypes in the preceding studies in that written language is a relatively recent human achievement in evolutionary terms and, unlike spoken language, typically requires explicit instruction. The team collated 175 genes of relevance for written language ability and investigated patterns of expression in various brain regions. One of their surprising insights includes the observation that most genes of interest for written language are not the ones that evolved recently; rather, humans created written representations of language using mainly ancient neural mechanisms. Another surprise is that some “reading” genes are most highly expressed prior to 24 postconception weeks and others, after that inflection point, with very different functional properties.

Beate Peter, Jennifer Davis, Laurel Bruce, Lizbeth Finestack, Miriam Kornelis, Linda Eng, Yookyung Kim, Nancy Scherer, Nancy Potter, Mark VanDam, Lauren Thompson, Susan Loveall, Carol Stoel-Gammon, Caitlin Raaz, Amy Armstrong-Heimsoth, and Sue Buckley show how insights from genetic investigations can be translated into clinical practice (Peter, Davis, et al., 2025). Here, we circle back to the world of medical genetics, where the concept of precision medicine emerged. Precision medicine is an approach that takes an individual's biological, environmental, and lifestyle related profile into account. By doing away with the “average patient” and instead tailoring diagnostics and therapeutics to the level of the individual, outcomes can be substantially improved. We borrowed these concepts from the world of medical genetics and translated them into the world of communication sciences and disorders. First, we addressed anticipated speech/language risks identified via newborn screenings into a prophylactic course of intervention called Babble Boot Camp. Second, we pointed out that dyslexia may arise from different endophenotypes of genetic origin such as neuronal hyperexcitability, opening the door for interventions targeting the brain's information processing modes instead of word-reading exercises. Here, we suggest that a genetic diagnosis does not have to be fate; it can be an opportunity for precision management, leading to improved outcomes.

Finally, a disclaimer: Not all human traits, whether related to speech, language, other behaviorally expressed conditions, or even medical conditions, are caused solely by genetic changes. We approach the study of genetics from a stance of humility and broad awareness of other layers of causality. Examples include the hormonal environment during prenatal development, mothers' nutritional status during gestation, preterm birth, young children's nutritional balance, infectious diseases, hospitalizations, the oral and gut microbiomes and their two-way connections to the brain, physical environments (e.g., air- and waterborne toxins), and social and cultural environments. If 86 billion neurons and 20,000 genes paint a dauntingly complex picture, think again: Maybe we are just scratching the surface here. Faced with such enormous entanglements, we celebrate every successful genetic discovery and the precision interventions it inspires.

Publisher Note: This article is part of the Forum: Research Symposium on Genetics in Communication Sciences and Disorders.

Funding Statement

This introduction stems from the 2024 Research Symposium at the American Speech-Language-Hearing Association Annual Convention, which was supported by the National Institute on Deafness and Other Communication Disorders (NIDCD) under Award R13DC003383.