When human beings work with material, shape material, the material shapes them at the same time. The potter centres the clay and the clay centrs the potter. While operating technology, technology affcets human beings as well. The mobile phone for example changed human decision behaviour. Interacting with material, including interaction with technology, shapes human beings and influences their spatiotemporal trajectories up to the point that others recognize them. In communities of practice the recognizing of spatiotemporal trajectries is a requirement for developing shared concepts out of which language emerges.