The article deals with the issue of studying the speech characteristics of a literary character, which is no doubt of significant interest. The speech portrait of a literary character is one of the key components in forming an image in a literary text. However, the speech of child characters, especially those with developmental disorders, has not received much attention. The source material for the study is the modern novel “The Curious Incident of the Dog in the Night-Time” by Mark Haddon and its translation into Russian.