@glover891, Erica l garrett, If device is newer return for warranty. Check if device is muted maybe, recheck all volume settings, try rebooting the device. If still not working possible a physical issue with the speaker and may need repair internally. You can try a factory reset to defaults, but this will wipe all the data on the tablet and will be like when received new. Below find a few trouble shooting forum links. Good luck.
I hope this helped you out, if so let me know by pressing the helpful button.
http://www.androidtablets.net/threads/rca-tablet-has-no-sound.71328/
http://www.tomsguide.com/forum/id-3181775/sound-rca-android-tablet.html
http://www.thriveforums.org/forum/toshiba-thrive-audio/5940-no-sound-coming-speakers-but-works-headphones-fix.html