When you attempt to put it into speaker phone mode, do you get a little speaker icon that tells you are on speaker phone? Is the volume turned up? Did you drop it or get it wet recently? There isn't much you can do to trouble shoot a problem like that. If you just got it, try to get it exchanged.
Not only may it void your warranty it will definitely void your warranty. You know this is a common problem with the Pearl, this is the first I hear about it happening on the Curve
