  The projected stellar rotational velocity ($v \sin i$) is critical for our
understanding of processes related to the evolution of angular momentum in
pre-main sequence stars. We present $v \sin i$ measurements of high-resolution
infrared and optical spectroscopy for 70 pre-main sequence stars in the
Taurus-Auriga star-forming region, in addition to effective temperatures
measured from line-depth ratios, and stellar rotation periods determined from
optical photometry. From the literature, we identified the stars in our sample
that show evidence of residing in circumstellar disks or multiple systems. The
comparison of infrared $v \sin i$ measurements calculated using two techniques
shows a residual scatter of $\sim$ 1.8 km s$^{-1}$, defining a typical error
floor for the $v \sin i$ of pre-main sequence stars from infrared spectra. A
comparison of the $v \sin i$ distributions of stars with and without companions
shows that binaries/multiples typically have a higher measured $v \sin i$,
which may be caused by contamination by companion lines, shorter disk lifetimes
in binary systems, or tidal interactions in hierarchical triples. A comparison
of optical and infrared $v \sin i$ values shows no significant difference
regardless of whether the star has a disk or not, indicating that CO
contamination from the disk does not impact $v \sin i$ measurements above the
typical $\sim$ 1.8 km s$^{-1}$ error floor of our measurements. Finally, we
observe a lack of a correlation between the $v \sin i$, presence of a disk, and
H-R diagram position, which indicates a complex interplay between stellar
rotation and evolution of pre-main sequence stars.
