The article deals with the history and current applications of concept of colloquiality (colloquial language). It outlines the history of the concept in Czech linguistics with focus on the stylistic characteristic associated with of colloquiality and points out some discrepancies in the usage of the concept in major grammars, dictionaries and other publications. Based on examples, especially from the media and communication in the educational setting, the paper argues that the stylistic variation of spoken Czech is largely misunderstood by its users. However, the concept of colloquiality still represents a valuable tool for the description of this stylistic variation.