It's unlikely to be user adjustable. We have bee spoilt by the likes of Android/Google who's philosophy is to let users choose how they like things. It's not LG's way and is frustrating.
Rise it with LG. They probably wont give you a solution but might tweak it in future software updates.
I get the feeling LG don't care what their customers want, as you can tell from the lack of an official forum, which I have asked them to setup.
When friends ask me what TV to buy I first tell them to steer clear of WebOS,
Is there a way of displaying better information in the name of audio tracks in the media player? It just says things like "English AAC" and I have some files with commentary tracks