  The charge response of charge-ordered state in the organic conductor
alpha-(BEDT-TTF)2I3 is characterized by dc resistivity, dielectric and optical
spectroscopy in different crystallographic directions within the
two-dimensional conduction layer. Two dielectric modes are detected. The large
mode is related to the phason-like excitation of the 2kF bond-charge density
wave which forms in the ab plane. The small dielectric mode is associated with
the motion of domain-wall pairs along the a- and b-axes between two types of
domains which are created due to inversion symmetry breaking.
