Not Speaking Without a Yichud:

Shortly before the passing of the Ropshitzer Rebbe zy"a, he accepted upon himself a “taanis dibbur", and he stopped speaking completely. This caused his family and chasidim a lot of pain, as they felt that they couldn't take care of him properly if he wouldn't say what he needed. His son, Rav Avrohom Chaim of Linsk zy"a, said to him, "My dear father, it seems to me that you have the ability to talk but you don't want to do so. At least tell me the reason for this." The Rebbe opened his mouth and said, "My son, you should know that from the time of my youth, I never said a single word without a 'yichud'. Now that I am week and can no longer do this, I decided that it is better to stop talking than to talk without yichudim."