Some of us gamers are old enough to remember a time when video games were voiceless. Sound effects were created by manipulating 8-bit synthesizers, which means there was no such thing as voice acting in video games. (The original Gameboy could synthesize simple vocal sounds, but not anywhere near well enough to do dialogue.) Eventually, more complex forms of audio were implemented, and this brought the human voice into our games. It was a rough road at first, but soon voiceovers would become a standard part of gaming.
Of course, this opened up a serious debate: between traditional text-based storytelling and voice acting, which is the most effective way to present a compelling story?
There are many angles from which to look at this debate, but let's start with the obvious: hearing a real voice in a game is a lot more immersive than having to stop to read text. When interacting with a person in real life, you are almost never going to have to read the things they say. So, when you meet a NPC in a game, it's usually better to actually hear that character's voice.
Voice acting, when done well, will suck you deep into the worlds of your favorite games. The original BioShock, for example, had some incredible voice talent. Lunar: The Silver Star Story, a game that is overlooked far too often, also contains some seriously memorable voiceovers. One of my all-time favorite uses of voice acting is the "Breencast" from Half-Life 2. Dr. Wallace Breen delivers passionate monologues over the loudspeakers while you fight your way through waves of Combine soldiers and auto-turrets. Not only are his speeches insanely well-written, the acting is absolutely perfect. Breen speaks quickly and intelligently, while tiny hints of neurosis slip through in the way he pauses between phrases or emphasizes certain words unnaturally. He presents himself as a powerful and smart man who is able to sell his twisted dogma especially well. And the icing on this cake is the fact that players don't ever have to listen to him if they don't want to; his words are purely background noise.
However, voice acting has the potential to be very bad. In the PSOne era, voiceovers in games were relatively new, and even games that are still considered classics had some extremely cheesy voice work. In Mega Man 8, Dr. Light's actor would often stumble over his lines, resulting in some hilarious blunders. The first Tenchu game was an incredible title that forced players to use stealth in some interesting and brand-new ways, yet the voice acting is among the worst ever in a video game. And who can forget the awful "master of unlocking" line from the original Resident Evil? (Google it if you want a good laugh.)
But even bad voice acting can have its place. For example, Silvia Christel from No More Heroes had one of the fakest French accents ever, which somehow managed to make her sexier than even her skimpy outfits and overwhelming confidence did. In fact, she's possibly one of the sexiest video game characters of all time, partially due to an accent that would make fluent French speakers cringe.
Of course, text has also had some famously bad implementations. Capcom's NES games were often riddled with spelling and grammar errors; a fact that is completely inexcusable since their entire games usually consisted of maybe ten lines of text. An English major could have proofread an entire game in under an hour, for crying out loud. And Capcom's tradition of using "D-minus English" even carried over into the PSOne era with the Resident Evil games.
Capcom wasn't even the worst company at using the English language. But honestly, how many of us would have ever heard of Zero Wing if it weren't for lines like "All your base are belong to us," and "somebody set up us the bomb," that came from the SEGA Mega Drive port?
RPGs tend to work better with lines of text than with voice acting though. One reason is that traditional RPGs often allow you to rename your characters. When the story uses text only, that works quite well. When there is voice acting involved, that's not often a possibility. In Lunar: SSS, for example, the protagonist is forever stuck with the name Alex.