Tatti was a Jalis storyteller during Adin's time who helped convince the Jalis to give Adin the Diamond.
Tales of Deltora
Tatti was dining in the feasting hall of Jaliad, seated on a stone platform near the fireplace, when Greel brought in his prisoner, Adin. Greel had allowed Adin to live and feast with the Jalis for the night as a reward for his valiant fight with the Jalis leader. Greel allowed Adin to explain why he had come to the Jalis' territory, suggesting that if the tale was amusing they would release and then chase him, but would kill him on the spot if he failed to entertain them. Adin described his quest to create a belt he had seen in his dreams, hoping to drive back the Shadow Lord. Tatti and the rest of the Jalis fell silent until Greel began to explain the Tenna Birdsong Tales to Adin, introducing Tatti as Tenna's direct descendant and the tribe’s current storyteller. Greel requested that Tatti tell the story of Opal the Dreamer.
Tatti complied, repeating the entire story, which spoke of a "man of iron and fire" — as Adin had described himself — and a belt like the one Adin had described. Her story enraptured Adin, who was astounded to hear a tale of his ancestor from a complete stranger. When she finished her tale, the Jalis cheered uproariously and Greel presented the Diamond to Adin.
Tatti was a frail-looking woman of considerable age with faded eyes, bony hands, and spotted skin.
Tatti appeared to take her position quite seriously. She did not speak except to relate the Tenna Birdsong Tales. When Adin described the Belt of Deltora, Tatti immediately recognised that he was the "man of iron and fire" spoken of in Opal the Dreamer's prophecy. The Jalis treated their storyteller with the utmost respect. 
Tatti was a skilled storyteller with a remarkable memory. As with all of the Jalis storytellers, she was able to remember every one of the Tenna Birdsong Tales verbatim. Her voice was much stronger than her withered appearance suggests, and her stories could be heard with ease from anywhere in Jaliad's feasting hall.