Comment by olyjohn

That may be a part of it, but I think for a lot of people the problem is how surround sound movies are processed.

Voice comes through the center channel. Music tends to come out of multiple speakers, and so do a lot of explosions and sound effects.

Most people don't have multi-channel setups at home. So you get everything coming out of 2 speakers or a sound bar.

What that means, is that you get 4+ channels of music and sound effects mixed into 2 channels. So it ends up drowning out the single voice channel.

When I play movies through Kodi, I generally go into the audio settings and turn up the center channel. This fixes the issue every time for me.