Programming languages and architectures can be diverse and specialized for certain niches of robot species. However, as soon as communication and networking are required between different kinds of robots, a lingua franca of interaction becomes reasonable. This is even more the case if robots are required to communicate with humans, for which robots that can use human-style communication is desirable. But this does not mean that all machines need to share the same programming language or architecture. Instead, behavior or interaction in the world might be a common interaction language. This implies thinking of machines as open systems in terms of interaction with the world.