Leon Cadogan was a Paraguayan of Australian parentage, self taught, who worked for years among Mbya Guarani communities and was eventually entrusted with material that had not previously been given to outsiders. His publications from the middle of the twentieth century, above all the collection of sacred texts he called Ayvu Rapyta, are among the most closely documented indigenous cosmologies in South America, and they were recorded in Guarani with his translations alongside.
The central idea is that speech and soul are the same thing. Ayvu means word or language, and the ayvu porĂ£ tenonde, the first fine word, is the beginning of creation: the creator Namandu unfolds himself, and the world comes from the word he founds. A person's soul arrives as a word soul, sent from the dwelling of the gods, and naming a child is therefore not labelling but discovering, since the ritual specialist's task is to learn which word has come and say it. Ordinary speech and sung prayer are on a continuum with that.
Alongside this sits the yvy marane y, the land without evil, a place reachable in some accounts by migration and in others by perfection of practice, and the historical Guarani migrations toward the coast in search of it are documented from the colonial period onward.
Two cautions belong here. Cadogan worked with particular communities, and what he recorded is Mbya, not a pan Guarani orthodoxy. And the texts were given to him in confidence, in a relationship built over years; some Mbya today have questioned how far material of that kind should circulate at all. The atlas records that the corpus exists and what it concerns, rather than reproducing the prayers.