I'm looking for a book that I read in the mid 90s.
It was about 3 sisters meeting Morgan le Fey in modern times and training to be witches. The overall plot assumes the legend if King Arthur was wrong, and Merlin was the evil one.
The three sisters all had one unique power to each of them, one of which was the power to talk to animals. The last notable thing I can think to mention was they called Excalibur by the name Caliborne, claiming that to be the true name of the sword.
I can remember is that the title does not give any hints to the inclusion of an Arthurian legend.