The Navajo traditionally celebrate a baby’s first laugh as it is seen as a sign they are leaving the spirit world and joining the physical one. Whoever draws out the first giggle is responsible for throwing a party known as A’wee Chi’deedloh, which is “hosted” by the baby. – WTF Fun Facts
Source: The Navajo Celebration of a Baby’s First Laugh – The Aesthetics of Joy by Ingrid Fetell Lee