The article by Dorothy V. M. Bishop and Margaret J. Snowling explores the relationship between developmental dyslexia and specific language impairment (SLI), two common developmental disorders that significantly impact a child's educational and psychosocial outcomes. Initially treated as distinct disorders, they are now often seen as different manifestations of the same underlying problem, differing only in severity or developmental stage. The authors argue that this view underestimates the independent influence of semantic and syntactic deficits in SLI, which affect reading comprehension and fluency in adolescence. The authors propose a two-dimensional model to conceptualize the relationship between these disorders, distinguishing between relatively restricted problems with literacy and more global difficulties in spoken language production and comprehension. They emphasize that while there are close behavioral similarities, it is helpful to retain a distinction between these two types of impairments. The article also discusses the diagnostic criteria for dyslexia and SLI, highlighting the limitations of traditional definitions based on IQ discrepancy. It suggests that a cognitive marker approach, focusing on underlying cognitive deficits rather than observed behavior, is more effective in identifying coherent groups of children. The authors review evidence from behavioral, etiological, and neurobiological perspectives to support their arguments. In terms of etiology, the article notes that both dyslexia and SLI tend to run in families, suggesting a genetic basis. Twin studies provide strong evidence for genetic contributions, though environmental factors also play a significant role. The authors conclude that while there are commonalities between dyslexia and SLI, they are best conceptualized as different points on a continuum of severity rather than as distinct disorders.The article by Dorothy V. M. Bishop and Margaret J. Snowling explores the relationship between developmental dyslexia and specific language impairment (SLI), two common developmental disorders that significantly impact a child's educational and psychosocial outcomes. Initially treated as distinct disorders, they are now often seen as different manifestations of the same underlying problem, differing only in severity or developmental stage. The authors argue that this view underestimates the independent influence of semantic and syntactic deficits in SLI, which affect reading comprehension and fluency in adolescence. The authors propose a two-dimensional model to conceptualize the relationship between these disorders, distinguishing between relatively restricted problems with literacy and more global difficulties in spoken language production and comprehension. They emphasize that while there are close behavioral similarities, it is helpful to retain a distinction between these two types of impairments. The article also discusses the diagnostic criteria for dyslexia and SLI, highlighting the limitations of traditional definitions based on IQ discrepancy. It suggests that a cognitive marker approach, focusing on underlying cognitive deficits rather than observed behavior, is more effective in identifying coherent groups of children. The authors review evidence from behavioral, etiological, and neurobiological perspectives to support their arguments. In terms of etiology, the article notes that both dyslexia and SLI tend to run in families, suggesting a genetic basis. Twin studies provide strong evidence for genetic contributions, though environmental factors also play a significant role. The authors conclude that while there are commonalities between dyslexia and SLI, they are best conceptualized as different points on a continuum of severity rather than as distinct disorders.