From Homing Beacon #128:

When General Grievous barks his orders, his minions scurry to carry out their tasks. His is a commanding presence, and his fearsome demeanor leaves no room for questions. His implacable metallic skeleton gives him the aspect of a droid, but hidden inside the armored carapace is an unwholesome, living being. To remind viewers of this inner Grievous, his words are occasionally punctuated with a hard, wet hacking cough -- suggesting that Grievous is literally rotten to the core.

Providing the voice of Grievous is Matthew Wood, whose history with Star Wars has been mostly behind-the-scenes. Though Wood is an actor, his contribution to the prequel trilogy has been primarily as Supervising Sound Editor. His access to the Episode III production process may have given him a head's up that casting was underway for the part, but the use of a pseudonym ensured that insider status didn't factor into the selection process.

On set, Duncan Young read Grievous' lines for the benefit of the actors. His voice was never intended to make it into the final film, and it was edited out of the mix early on along with much of the production audio. Ben Burtt and others supplied temporary voices on the track, all heavily modulated to be appropriate for a cyborg general.

"We put out a casting package of those modulated voices, looking for voice actors," says Wood. "Chris Scarabosio processed each one, and we would play these for George for him to evaluate. We went through a lot of different people, and on the last package we sent out, I put my own voice on there, though I didn't put my name on it."

With the pseudonym "Alan Smithee," Wood's reading of Grievous was played for Lucas without introduction, and he selected it. "It was great, but then I thought, 'should I tell him that it's me?'"recounts Wood. "When George found out, he said 'Great, let's record him tomorrow.'"

In a three-hour recording session, Wood laid down all of Grievous lines. "He's definitely an evil character. He's the leader of the droid army, but not a droid. He feels things; he feels things extremely, I would say. It's a lot of yelling, and shouting out orders, so it had a lot of drill sergeant to it."

While studying acting at American Conservatory Theater in San Francisco, Wood came across a website that offered samples of various accents to help actors hear and mimic patterns of speech from around the world. "You could hear the same line of dialogue read in different accents," he says. "I liked the sound of the Eastern European and Romanian accents. Also, I had just come back from Prague, so I had that in mind for Grievous."

In the finished film, Grievous' voice will undergo some sort of processing. Currently, it is lowered in pitch and has a ring modulation to it. That may change as the audio mix is still being put together. Wood offers the caveat that everything may still change, having witnessed all the prequels being made. "But I did also record Grievous for the Episode III videogame. I did 125 lines of dialogue for that."