what's the best way of using subtitles?

i wan’t to show subtitles in my game, i don’t want a complex dialogue sistem, it’s gonna be some kind of monologue, the player walks through a trigger box and the narrator says something, i wan’t to be able to show subtitles (if the player enabled it in the menu) whenever the narrator says something (in the language the player selected in the menu), i’m ok with the menu part, but i was wondering what’s the best way of showing the subtitles, i don’t know if there’s a built in system for this, i was thinking about showing it in a text box in the HUD, but i couldn’t get a reference to the HUD to call it’s functions/events, someone know a way to help me?