Hello, I have nearly completed a j2me game and I am wondering how important it is to include sound in a game. I believe most people play games on their phones outside of their home (while they are commuting to work/waiting for a train/waiting for a friend/at their desk at work/on lunch breaks etc). In this case it is preferable to have sound turned off so as not to annoy other people. In addition, when the sound is turned on, the low quality of it hardly makes the game a more enjoyable experience.
It depends on what kind of a game it is, and also who the user is going to be.
People do expect good sounds (not too loud, not too annoying).
Sound provides for a good feedback channel (in addition to, e.g., vibration) besides what's shown on the display.
And people expect to be able to decide for themselves (apps must have a way to turn on/off game sounds, background music, control their volume separately, etc.).
In other words, I wouldn't forget about sounds. If you as a game developer decide to leave out sounds, some will like it, others will hate it, some may not care either way. If you want to please the widest group of users, the sounds must be there, but controllable (as described above), and they should be good, pleasant and fitting for the game.