Extreme Programming in development of specific software

The paper shows experiences with using Extreme Programming (XP) for specific projects. XP practices Test-Driven Development, pair programming, short interaction, a team code ownership and acceptance tests. Author writes about possibilities of information technologies when improving communicative skills of children with specific disorders, such as autistic spectrum disorders, Down syndrome, mental retardation, etc. The development of an application stemming from the communication system PECS (The Picture Exchange Communication System) and its Czech variant VOKS is the base of this paper to show specificity of the development and verification of software for the given group of handicapped users. The paper shows suitability of using agile methods of software development for a concrete application which is designed for users with specific disorders. It tries to show advantages and disadvantages of new methodologies, particularly Extreme Programming. This agile method prefers fast reaction to a change before the plan completion, which proved to be important in the case of the developed software. There were plenty of changes and new requirements during the development, and their solution was more important for the output quality than following the time schedule of the development.