  We investigate the dynamics of a fluid of dipolar hard spheres in its liquid
and glassy phase, with emphasis on the microscopic time or frequency regime.
This system shows rather different glass transition scenarios related to its
rich equilibrium behavior which ranges from a simple hard sphere fluid to a
long range ferroelectric orientational order. In the liquid phase close to the
ideal glass transition line and in the glassy regime a medium range
orientational order occurs leading to a softening of an orientational mode. To
investigate the role of this mode we use the molecular mode-coupling equations
to calculate the spectra $\phi_{lm}^{\prime \prime}(q,\omega)$ and $\chi
_{lm}''(q,\omega)$. In the center of mass spectra $ \phi_{00}''(q,\omega)$ and
$\chi_{00}''(q,\omega)$ we found besides a high frequency peak at $\omega
_{hf}$ a peak at $\omega_{op}$, about one decade below $\omega_{hf}$. $\omega
_{op}$ has almost no $q$-dependence and exhibits an ``isotope'' effect $\omega
_{op}\propto I^{-1/2}$, with $I$ the moment of inertia. We give evidence that
the existence of this peak is related to the occurrence of the medium ranged
orientational order. It is shown that some of these feature also exist for
schematic mode coupling models.
