For simple Bash scripts MPlayer is probably a bit too heavy and too verbose in terms of output. A built-in option is
canberra-gtk-play which comes preinstalled on Ubuntu:
Note: it uses the alerts volume, and you must pass
--file= in order to play a file from a path.
It can also play a sound by id which represents the file name without extension of media files under
/usr/share/sounds (apparently this only works for sounds that are registered as part of a sound theme):
Another option is using the gstreamer command-line tools which are present on most modern Linux boxes:
gst-launch-1.0 playbin uri=file:///usr/share/sounds/ubuntu/stereo/message.ogg
To suppress all output redirect it to
gst-launch-1.0 playbin uri=file:///usr/share/sounds/ubuntu/stereo/message.ogg > /dev/null 2>&1
gst-launch-0.10 might be present on your system.