This is a very common problem exacerbated by multi-channel audio tracks and super thin televisions that have the speakers pointed down or even backwards. Soundbars can help but they produce a surround-sound experience which can make it even more difficult to understanding television dialog.
The best solution is a headset or a speaker that amplifies human speech frequencies (500 to 2500 Hz) and reduce background sounds (0 to 500 Hz) so the television dialog jumps out from these complex audio tracks. Hearing aids are designed to do this, but they amplify every noise in the room. TV Ears also does this but has the advantage of amplifying the television dialog directly into your ears.