Q 3. (See questions 3379 – 80 above) Could I rotate the hours of the Tzom Dibbur, or do they have to be static, for example, from 8am to 10am?
A. On question 3354 regarding how to tell others that one is engaged in a Taanis Dibbur we wrote: Some Tzadikim like Horav Sholom Schwadron zt’l who often kept a Taanis Dibbur, would simply keep on repeating the Tehilim that they said by heart and just pointed to their mouths. The ones who were familiar with him, understood that it was one of the occasions of Taanis Dibbur.
It is interesting to mention that Horav Schwadron, was one of the most popular speakers and a true master of words, yet it is known that he did not speak on Monday and Thursday and often Shabbos as well. In addition, during the forty days from Rosh Chodesh Elul to Yom Kippur, he never uttered a word except for davening or learning.
See also question 487 regarding the redeeming a fast for the dropping Tefilin. Chaim Shoal (1: 12), maintains that the aged or ill, can redeem that fast if it will affect their learning, by keeping a Taanis Dibbur (restrain from speaking non- Torah conversations) for a day.
Horav Shlomo Miller’s Shlit’a opinion is that as mentioned above one may accept this important type of fasting, according to what one is able to do.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a