What computer operating system is involved with your Premiere Elements 11?
Have you gone through the usual of checking the Edit Menu/Preferences/Audio Hardware ASIO settings Output settings?
Is the problem restricted to the narration created with the Narration Tool and played back on the Narration Track or to any audio placed on the Narration Track? Is all other sound heard inside and outside the project? What microphone are you using to create this narration?
Depending on your other answers, what happens if you move the narration clip (no sound) from the Narration Track to a new number audio track above?
Is your computer updates updated?
Please consider, supply more information, and then we can plan troubleshooting strategy.