The talking pig is a combination of 48 real Yorkshire pigs plus an animatronic double. A makeup artist added toupee and eyelashes to each, and computer digitization manipulated pictures of the snout to make the pig appear to talk.
When James Cromwell was handed the screenplay for Babe, he thumbed through it to see how many lines he had. He saw that he didn't have that many, he decided that he would do it as a nice easy film. What he didn't realize was that he would have more screen time in this film than any of his previous films.
Magda Szubanski was only in her early 30s when she won the role of Esme Hoggett, who was supposed to be elderly, so Szubanski was made up to look about 20 years older than she actually was at the time.