  We have obtained high-dispersion spectra for four massive star clusters in
the dwarf irregular galaxies NGC 4214 and NGC 4449, using the HIRES
spectrograph on the Keck I telescope. Combining the velocity dispersions of the
clusters with structural parameters and photometry from images taken with HST,
we estimate mass-to-light ratios and compare these with simple stellar
population (SSP) models in order to constrain the stellar mass functions (MFs).
For all clusters we find mass-to-light ratios which are similar to or slightly
higher than for a Kroupa MF, and thereby rule out any MF which is deficient in
low-mass stars compared to a Kroupa-type MF. The four clusters have virial
masses ranging between 2.1E5 Msun and 1.5E6 Msun, half-light radii between 3.0
and 5.2 pc, estimated core densities in the range 2E3 Msun pc^-3 to 2E5 Msun
pc^-3 and ages between 200 Myr and 800 Myr. We also present new high-dispersion
near-infrared spectroscopy for a luminous young (about 15 Myr) cluster in the
nearby spiral galaxy NGC 6946, which we have previously observed with HIRES.
The new measurements in the infrared agree well with previous estimates of the
velocity dispersion, yielding a mass of about 1.7E6 Msun. The properties of the
clusters studied here are all consistent with the clusters being young versions
of the old globular clusters found around all major galaxies.
