Abstract: An animation system includes a voice engine which processes audio input signals, typically speech signals, and converts them to a digital signal for processing. The digital signal is analysed to generate a value characteristic of each sample of the input signal and which is related to the maximum amplitude of the sample. The voice engine compares each value obtained in this way to the number of possible predetermined value ranges corresponding to a predetermined graphic showing a mouth position, and thus matches the input speech signal to a variety of possible mouth positions. The mouth graphics are superimposed on an image of a character substantially in real-time, providing an animated display of a character with its mouth synchronised to the input speech signal.