The document discusses trying to determine the sounds mice make. While a Pikachu says "Pika...chuuuuu!", the document does not reveal what one mouse says, only suggesting potential sounds like chirp, squeak, and sniff. It is proposed to use cheese to lure mice and get their sounds, ending with an onomatopoeic summary of "Chirp chirp squeak squeak sniff sniff" for mice noises.