Because I'm snotty, and I hate typing commands in caps, I've got a symlink from MP4Box to mp4box on my box, hence the examples being lower case. MP4Box dumps output to stderr, so I get to be snotty in return. :D

Display information about a file, its video or audio track:

mp4box -info media.mp4
mp4box -info 1 media.mp4
mp4box -info 2 media.mp4

Set language to English on (all) tracks:

mp4box -lang eng media.mp4

Set a title for the video (the first track). Note that I haven't been able to get things like apostrophes to work. Haven't dug much into it either, though.

mp4box -name 1="classy video title" media.mp4