The Princeling's Lament
http://na.leagueoflegends.com/en/featured/shadow-isles#/the-princelings-lament?_k=g3c8ud if you haven't read this amazing poem (or taken the lazy time and listen to it (which is actually more important with something I'm gonna go over later)) go do that now.... Okay, done? Awesome poem isn't it? Giving major props to whoever wrote it. Now, for the fun part, the lore. Spoilers be warned, they will be here, and why are you still reading this if you didn't already read it
So a prince is getting married and his wed is poisoned and dies, so he attempts to go take the fools errand of going to the Shadow Isles to find something to revive her, and has a few run ins with some of our favorite champs from the Isles. however, he is a selfish prick and poisoned her himself so he could have all the glory. Unluckily for him, with her dying breath she made a bond with Hoppy Hoppy Bitchney Spears because that is what she sorta does. in the end it didn't even matter because he is killed by her and he doesn't even join the Isles, Thresh gets him, and he deserves this
So, what has to do with the voice, well, that voice doesn't seem like any of the champions we know today, except maybe the Death Pope, but it is a story that involves a dead female monarch and the corresponding male going to the Isles for something to revive her, for totally different reasons however, this poem is clearly a warning though, don't go to the Shadow Isles, and what is dead should stay dead. So, once again, what does this have to do with the voice? Well, there is one lore character this may be, our recently highly referenced Ruined King. It would make since he could have a poem like this, telling people plain and simple, don't fuck around with things that are dead and stay away from the Shadow Isles.
TL:DR: I think the poem voice is a teaser for the Ruined King as a champion, also READ THIS POEM IT IS AMAZING