Originally Posted by HangFire
Originally Posted by MrMoody
Originally Posted by ARCOgraphite
There may also be an issue with the 5.1 to stereo mixdown.
This is the most likely problem. If you have surround, you can adjust the center channel gain and correct it. Some equipment has a dialogue level/enhancement setting that will help.
I agree. I had this issue on a Sony and a Yamaha X.1 system, where X > 5. For some reason all the dialog went into the Center speaker, which was defaulted to almost no volume, even after a sound calibration. The fix was to lose the included mic, ignore the stupid sound calibration, and adjust all the speaker levels for the reality of my situation.
OP doesn't have a receiver and external speakers. He's using the built-in speakers in his TV, so I doubt there is a away for him to adjust center channel volume. However, there are probably different surround modes available for him to choose from, hence my earlier suggestion to play around with those and see which one sounds best for dialog. Or try switching the surround mode off completely.