I had to find a voice that sounded like someone ‘golluming.’ I wanted this sense that his body is controlled by [the ring] so that it’s an involuntary action that was making him sound like this. I looked to one of my cats, Diz, who came in while I was working on the character and coughed up a furball. This became really interesting to me because you watch a cat throwing up a furball and it’s like the whole body writhes from the tip of the neck to the tip of the tail and convulses. And you see this ripple goes down its spine.
— Isn’t That Precious: Andy Serkis explains how he created the voice for Gollum.