To cite this article: Leonie Sandercock (1999) Expanding the 'language' of planning: A meditation on planning education for the twenty-first century, European Planning Studies, 7:5, 533-544, ABSTRACT What kinds of knowledge do planners need in a post-modern age in which cities and regions are characterized by fragmentation, polarization, and 'difference' in its many guises? This paper identifies four dilemmas of traditional planning education: the reduction of 'knowledge' to a set of measurable skills; the ossifying of programmes around a core which reinforces an outdated modernist paradigm; the loss of focus on questions of meaning, of value, of the spirit, which has resulted from a divorce between planning and design education; and the tendency to draw tight boundaries around professional identity, which prevents a truly interdisciplinary practice from emerging.Preparing planners for the challenges of the twenty-first century might involve the following: identifying the specificity of the domain of planning in a more dynamic way so that the core does not become redundant every decade; articulating planning programmes with environmental and design programmes; shifting from an emphasis on skills to key literacies (five are identified); approaching planning as an ethical inquiry.Interdisciplinary ... is not just a question of putting several fields together, so that individuals can share their specialised knowledge and converse with one another within their expertise. It is to create sharing in a field that belongs to no-one, not even to those who create it. What is at stake, therefore, in this inter-creation is the very notion of specialisation and of expertise, of discipline and professionalism.