Developmental language disorder (DLD) is a neurodevelopmental condition that emerges in early childhood and frequently persists into adulthood. People with DLD have significant difficulty learning, understanding, and using spoken language. Under U.S. Public Law 101-476 (Individuals with Disabilities Education Act [IDEA], 2004; first issued in 1990 and reissued in 2004), children may be eligible for school-based services, typically under the category “speech-language impairment,” if their DLD affects educational performance and requires specially designed support. DLD is one of the most common neurodevelopmental disorders. With an estimated prevalence of 7.58% (Norbury et al., 2016; see also Tomblin et al., 1997), it is nearly 7 times more common than autism spectrum disorder (ASD; prevalence = 1.1%; Brugha et al., 2012) and 46 times more common than permanent childhood hearing impairment (prevalence = 0.165%; Fortnum et al., 2001).
As a population, people with DLD face significant risks. Compared to other students, those with DLD are 6 times more likely to have reading disabilities, 6 times more likely to have significant spelling problems, 4 times more likely to struggle with math, and 12 times more likely to face all three of these difficulties combined (Young et al., 2002). People who have DLD are 6 times more likely than others to experience clinical levels of anxiety and 3 times more likely to have clinical depression (Conti-Ramsden & Botting, 2008). Girls with DLD are 3 times more likely to experience sexual abuse (Brownlie et al., 2007). Boys with DLD are 4 times more likely to engage in delinquent behavior (Brownlie et al., 2004). Adults with DLD are twice more likely to go over a year without employment than other adults (Law et al., 2009).
Without a doubt, DLD is a common condition that limits the health, happiness, and success of many who live with it. Nevertheless, people with DLD are underserved, and the condition itself is under-researched. The reasons are complicated, but the consequences of continued failure are dire. This clinical focus article is a call to action. I will provide evidence to demonstrate the ways that we, as a profession, are failing children with DLD; explore the reasons for these failures; and encourage change. The institutions and policies that dictate, support, or constrain clinical services and research efforts vary widely from country to country. This review is admittedly United States–centric, with some attention paid to the United Kingdom as well, but it is my hope that some of the points raised here are universally relevant.