I haven't tried to turn it off because that is part of the draw for me, especially since there are subtitles, but I thought there was a volume slider you could turn down to 0 for the voices

tip:
if you listen a foreign language while reading subtitles that were properly translated (ie without or almost zero "localization" bs) you can gradually learn some words a be less "annoyed" from ignoring them or getting distracted. you should try this, if you like japanese media (specially anime with "fan subs", which are often more accurate to "official ones", because often the official western translations have been made by activists trying to force new ideas or dialogues that misrepresent or distort completely the original stories).

still, i agree is always useful to be able to turn off volume of voices, sound effects and music individually, depending how you want to play.