This book deals with sociolect as it is used in Chaucer’s Canterbury Tales. Its goal is to find and describe the connections between particular characters and their social profiles. This goal leads to the following hypothesis: Chaucer described the characters on the basis of social stereotypes. Each of these characters uses certain language style which can be defined as a sociolect. The work consists of two main parts. The first theoretical part is focused on what a sociolect is, as well as the development of the English language in the 14th century and the life of Geoffrey Chaucer. Furthermore, it explores the English social history of the 14th century England, which is the key to understand the social profiles of Chaucer’s characters. The following analytical part presents a description of the characters, hypotheses about their styles and the stylistic analyses of the language of the selected stories. Finally, the conclusion presents the answers to the questions from the introduction and more importantly, it explains why the principle hypothesis has been proved only partly.