From my talk at Interactions 12 in Dublin on February 2, 2012.
You know how you can recognize a Porsche sports car regardless of the model or year? This is effective design language at work. A design language establishes the visual vocabulary, relationships and hierarchies that allow diverse products to become recognizable and unified. This tool has long been used in industrial design to create coherent families of products. But as products become digital and shift to multi-platform app-driven ecosystems, what constitutes an effective design language for interaction that can drive consistency across these varied experiences?