An anonymous but trusted source has provided us with new information regarding Portal 2. According to said source, casting for voice actors for Portal 2 has begun. We were sent numerous e-mails, including a description of one of the game's new characters, Cave Johnson (and concept art for that character), and a sample page of the game's script. Check it all out after the jump!

CAVE JOHNSON (ECCENTRIC DEAD BILLIONAIRE)] Cave Johnson is a character for a new game in the Portal series from Valve Software. Portal is a dark comedy; the role will require comic timing, with occasional dramatic moments. Age: early 60s. He is founder and CEO of a successful applied science company, a self-made billionaire who's learned to trust his gut and doesn't sweat the details—is a big picture thinker. He might not know how science works, but he knows how people work. Used to getting what he wants. Extroverted, enthusiastic and opinionated. High energy: life is an adventure he's happy to be on. A born salesman, a leader, an evangelist. People trust him, even when his plans are clearly dangerous. Speaks with a slight Southern/Western accent (natural, not too broad). He a uses warm, homespun delivery to put people at their ease. He doesn't accept the responsibility that comes with his power. Either he doesn't see or chooses not to see the ramifications of his actions. Goes from sidekick to principle antagonist. Sarts to lose his grip on his humanity as the story progresses. As he isolates himself from the people around him, he loses touch with reality...VOICE OVER ONLY [sic]

And here's the script sample page:

Cave Johnson

Dialogue Samples

(Introducing himself over a loudspeaker to the Player)

Welcome, friend! I hope you enjoyed yer brief detention in the Relaxation Vault. Cave Johnson here, founder and CEO of Aperture Science -- the best damn applied sciences company on Earth. How good is the science here? Get a load a' this: I am dead! Now, yer probably askin' yourself, "Cave, come on now. How is this possible? Are you some manner of Dracula? Or Frankenstein? Or dependin' on yer cultural heritage, a Blackula or Latin Frankenstein? No sir! It's science. As of this mornin', yer old buddy Cave has been resurrected inside of a computer. And I never felt better!

You may also be askin', "Cave, where am I? When can I leave? Am I in danger?" Let me answer them questions, with a question. "Who is ready for a science adventure?" Yeah! I hope the answer is you! Because the test starts in three… Two… Go!

(Cave congratulates you on your success)
Masters level testing: Completed! Hell, crushed! You. Are. A. Genius.

(Cave contemplates the afterlife)
I been thinkin. Heck, suspended as I am in this inky purgatorium, I got nothin' to do but think. What if them engineers didn't do me no favors pourin' me into a computer? What if they denied me my final reward? Lemme tell ya about a fella. Lived thousands a years ago. Didn't want nothin' but fer folks to be a little bit nicer to each other. And in the end, he sacrificed himself to save us all. You know who I'm talking about: Hercules.

The man battled minotaurs! Medusas! Hell, he put the gods themselves in an arm bar. And for overcomin' all them trials? He got to go to Olympus. Damn it! I battled my monsters! Where's my Olympus? Unless… I haven't killed all my monsters… Anyway, this next test. Whoo… Yeah… Good luck with that…

So, there you go. Sounds pretty much in line with the writing style of the original Portal. According to the e-mails we were sent, recording is planned to begin in July.