Hans Asperger studied mental abnormalities in children in Vienna, Austria, in the early twentieth century. Asperger was one of the early researchers who studied the syndrome that was later named after him, Asperger's Syndrome. Asperger described the syndrome in his 1944 publication Die Autistischen Psychopathen im Kindesalter (Autistic Psychopathy in Childhood). At that time, the syndrome was called autistic psychopathy, and Asperger noted that characteristics of the syndrome included lack of sympathy, one-sided conversations, and difficulty forming friendships. Asperger's work led to the recognition of Asperger's Syndrome as a disorder that results from abnormal development, and the syndrome was later classed on the autism spectrum.

In 1990, researcher Jane Hurst and her colleagues published “An Extended Family With a Dominantly Inherited Speech Disorder,” in which they proposed that a single gene was responsible for a language disorder across three generations of a family. Affected individuals of the family, called the KE family, had difficulty producing, expressing and comprehending speech. Hurst and her team studied the KE family and the disorder at the Department of Clinical Genetics at the Great Ormond Street Hospital for Children in London, England. Their report was subsequently published in the journal Developmental Medicine and Child Neurology in 1990. The authors’ conclusions helped researchers better describe and explain language as a developmental and biological phenomenon and led later researchers to discover the proposed gene, mutations to which caused the language disorder.