The Purity of Rav Yitzchok of Volozhin's Speech:

Rav Yitzchok of Volozhin zt"l was extremely careful with his words. He avoided any trace of lashon hara. He once needed to say that a certain person was liar. Since he didn't want to say that word, he said, "This man has a great memory. Some people remember things that happened 10 years ago. Some even remember things that occurred 20 years ago. Those with the best memories can recall events even from 50 years ago. But this man has an incredible memory that he remembers things that never happened at all."