  We discuss the large $N$ expansion in backgrounds of extended states with
focus on implementation of Goldstone symmetries and the construction of the
associated Hilbert space. The formulation is given in the general framework of
collective field theory. Case of translational symmetry is described first, as
the basic example. The large $N$ thermofield represents the main topics, with
the emergent dynamics of Left-Right bulk fields and collective symmetry
coordinates. These give the basis for a $1/N$ expansion.
