I've seen videos on YouTube and Guild wars 2 was voice but when I played it, it was not do you guys know why? Is it that the whole game is not voiced, I'm in a beginner area, or I have to buy an extension/membership?
If you are hearing no voice at all, this could be due to your sound or language settings or simply the game has not downloaded the sound files at that point - it is playable way before the download is completely finished.
Not everything in the game has a voice over, but most npc idle dialogs, cutscenes in personal story and player character reactions are.
But it is not necessary to have bought an expansion, to play with voice over - this is already a feature in the core game.