When Nick Park and Peter Lord came to visit our office a couple months back, we asked them about the genesis of the idea for the original Creature Comforts short. Aardman was commissioned to make several short films using unscripted audio for a series called Lip Synch, and Nick Park's piece was the Creature Comforts short in 1989. Peter Lord mentioned that one of the first, if not THE first animated piece to use audio recorded from real people rather than actors was Moonbird (1959) which won an Oscar for best Animated Short. John and Faith Hubley had a unique collaboration and made over 20 independent, animated films together. You can learn more about them here.
Moonbird featured the voices of their children at play and the result is a beautiful short film which has been uploaded to YouTube for our viewing pleasure: