When the Blessed Virgin appeared to Saint Juan Diego and imprinted her image upon his cloak, she also appeared to his sick uncle Juan Bernardino and cured him. She gave the uncle the task of telling the bishop what her image should to be called. In the account recorded in the Aztec language the title she gave herself translates as "The Perfect Virgin, Holy Mary of Guadalupe" and the non-Aztec word "Guadalupe" appears amongst the Aztec words. But is this what the Blessed Virgin actually said to Juan Bernardino?
The Aztec language of Nahautl does not contain the letters "G" and "D" found in Guadalupe. Could the uncle have spoken the word Guadalupe or articulated it well enough to be understood?
The Belgian Jesuit Francis Johnston studied the matter exhaustively, and 1931 he wrote "It was expected that Our Lady would give Juan Bernardino a message of such transcendental importance in his own language, so that he could remember the words and accurately repeat them, instead of a message containing an Arabic word like Guadalupe which could not be spelt or pronounced in Nahautl."
It seems likely that Mary said something in Aztec to Juan Bernardino: something familiar to his ear and tongue, and something meaningful to the Indians, but something that was misunderstood by the bishop as meaningful to him and the Spanish -- in this case, the shrine by the name of Guadalupe back in Spain.
Father Johnston said Becarra Tanco, who participated in the Apostolic Proceedings of 1666, concluded that Mary used the word "Tequantlaxopeuh," which in certain dialects of the Nahautl tongue would be pronounced very similarly to "Guadalupe." It means "she who saves us from the devourer" and also translated as "she who steps on the serpent."
This could be understood in the general sense of the Blessed Virgin's triumph and power over evil, as foreshadowed in the Book of Genesis: "I will put enmities between thee and the woman, and thy seed and her seed; she shall crush thy head." But the results of the Virgin's apparition also points to another more specific and local interpretation.
To the ears of the Aztec Indians, when the Virgin identified herself this way she was saying she had suppressed and supplanted Quetzalcoatl, idolized in stone as a serpent and to whom countless innocents were sacrificed. It was wonder and joy that the Indians received the news of her apparition to one of their own and the building of a church for them. In the seven years following the apparition eight million natives were baptized. The conquistador Fernando Cortez himself marched in procession to the dedication of the cathedral.
Read the actual contemporary account of the Apparition of Our Lady to Juan Diego.