Where do you find the song sang to Giegue in the end of mother

You find the song in eight different parts scattered in different places in the world of MOTHER. The first part is found in one of Ninten's sister's rooms and the second is found in the Canary Village when you return the canary you can buy in the department store to Singing Laura.

The third part you can hear from the Singing Monkey after defeating the Starman Junior in Cream Puff Zoo. The fourth part can be heard at the end of a maze from a piano in the Rosemary's Haunted House.

The fifth part can be heard from a cactus somewhere in Advent Desert. The sixth part is sheet music obtained from a Dragon in Magicant Dungeon after defeating it. The seventh and eight parts are found on Holy Loly Mountain.

Part seven is technically found at the bottom of the lake. Lloyd has to take the motorboat into the centre and go into the whirlpool. After recruiting EVE, the final party member, continue climbing the mountain and beat the boss. After that, continue and interact with George's tombstone to find the final part.

Once that is over, return to Magicant and talk to the Queen Mary, and then she will fit the parts together and give you the song.

If you mean the actual song itself, just type in "Eight Melodies" on Youtube. You should find it easily.