  Efforts are underway to improve the design and sensitivity of gravitational
waves detectors, with the hope that the next generation of these detectors will
observe a gravitational wave signal. Such a signal will not only provide
information on dynamics in the strong gravity regime that characterizes
potential sources of gravitational waves, but will also serve as a decisive
test for alternative theories of gravitation that are consistent with all other
current experimental observations. We study the linearized theory of the
tensor-vector-scalar theory of gravity (TeVeS) with generalized vector action,
an alternative theory of gravitation designed to explain the apparent deficit
of visible matter in galaxies and clusters of galaxies without postulating yet
undetected dark matter. We find the polarization states and propagation speeds
for gravitational waves in vacuum, and show that in addition to the usual
transverse-traceless propagation modes, there are two more transverse modes and
two trace modes. Additionally, the propagation speeds are different from c.
