The Wisp Whistle is an item in Ultima VII that allows the Avatar to speak to Wisps.
In Ultima VII, the Wisps show at first no interest in the Avatar, being totally absorbed in their studies of the Emps. However, this special whistle calls their attention to the Avatar when played.
Trellek told the Avatar that a special call from the Emps caused the Wisps to turn their attention to them. Trellek offered to join the Avatar to help the hero with that problem. Since Trellek was in the end forbidden to accompany the Avatar on this Quest by his wife, he made a special whistle, with which it was possible to emulate the call to attract a Wisp. With the Whistle, it was possible to talk with the Xorinite Wisp.