The occurrence of tangential speech (a response that does not answer a question, or a question or comment not related to the current topic, and all such speech that disrupts the normal flow of conversation) was quantified at the New York State Institute for Basic Research in Developmental Disabilities in 10–15 minute taped structured conversational samples. Thirty subjects with a mean chronological age between 14.6 and 19.7 years (range 6 to 35 years) and a mean language age between 5.19 and 5.68 years (range 4 to 8 years) were studied. Ten male subjects had Fragile X syndrome, 10 male subjects had autism without Fragile X syndrome, and 4 male and 6 female subjects had mental retardation without Fragile X syndrome or autism. Tangential language was present in a much higher percentage of the speech of children with Fragile X (indeed, almost exclusively) than in those with the other 2 conditions (P<.00002 compared to mental retardation and P<.0005 compared to those with autistic disorders). The authors hypothesize that this may be due to the association of tangential speech with the social avoidance that characterizes this syndrome.
Pediatricians are accustomed to listening for deficits in a child’s pronunciation, vocabulary, sentence length, and syntax. Other language phenomena that may also provide clues to the presence of linguistic or other developmental problems include echolalia (non-communicative parroting), pragmatic deficits (such as difficulties in conversational turn-taking), and tangential language. Tangential language can occur in mental retardation, autism, Fragile X syndrome, attention deficit hyperactivity disorder,1 and schizophrenia. The present paper emphasizes the different rates at which tangential language characterizes three different neurodevelopmental syndromes. Language profiles are now being employed in behavioral phenotyping and, therefore, closer attention to a child’s linguistic behavior is becoming increasingly important in genetic syndrome subtyping.