In this paper, we examine the contribution that pattern languages could make to user participation in the design of interactive systems, and we report on our experiences of using pattern languages in this way. In recent years, there has been a growing interest in the use of patterns and pattern languages in the design of interactive systems. Pattern languages were originally developed by the architect, Christopher Alexander, both as a way of understanding the nature of building designs that promote a 'humane' or living built environment; and as a practical tool to aid in participatory design of buildings. Our experience suggests that pattern languages do have considerable potential to support participatory design in HCI, but that many pragmatic issues remain to be resolved.