  It is well known that perspective alignment plays a major role in the
planning and interpretation of spatial language. In order to understand the
role of perspective alignment and the cognitive processes involved, we have
made precise complete cognitive models of situated embodied agents that
self-organise a communication system for dialoging about the position and
movement of real world objects in their immediate surroundings. We show in a
series of robotic experiments which cognitive mechanisms are necessary and
sufficient to achieve successful spatial language and why and how perspective
alignment can take place, either implicitly or based on explicit marking.
