It is customary that after concluding the “Hatov Ve’Hametiv” blessing of Birkat Hamazon (which ends off with the words “Ve’Revach Ve’Hatzalah Ve’Chol Tuv”), we recite a series of requests all beginning with the word “Harachaman” (“May the Merciful One etc.”). There are several different versions among different communities with regards to the “Harachaman” texts, for this section was not drafted by the members of the Great Assembly (end of the period of the prophets during the Second Temple era); rather, this was a customary text adopted by the Jewish nation later and therefore, there are several variances.
One may, in fact, add one’s own personal requests into the “Harachaman” section that do not appear there already. For instance, within the context of the “Guest’s Blessing” where one recites “May the Merciful One bless the owner of this house etc.” one may add as many blessings to the head of the household as one wishes as long as one knows how to articulate this in a proper manner.
When guests were seated at his table, Maran Rabbeinu Ovadia Yosef zt”l would customarily add his own blessing to them, as follows: “May the Merciful One bless all of those seated at this table with longevity, wealth, honor, excellent health, and abundant Parnassah.”
The custom of reciting the “Harachaman” texts is already quoted by the Rishonim, as the Tur (Chapter 189) states: “It is customary that after the ‘Hatov Ve’Hametiv’ blessing, one recites a series of various requests in the form of ‘Harachaman.’” Indeed, the Ohr Zarua (Chapter 199) states that the “Harachaman” texts are recited on Shabbat as they are on weekdays. He proceeds to quote several “Harachaman” texts that were customary at that time, such as, “May the Merciful One save us from poverty” and “May the Merciful One avenge the blood of His servants.” Similarly, the Meiri writes in his Sefer Magen Avot (Chapter 24) that it is customary for every individual to add to this series with personal requests as one wishes.
Let us now discuss whether or not it is permissible to speak in the middle of the series of “Harachaman” texts, for since reciting these texts are merely based on a custom, it would seem that one may speak between each of these requests for whatever reason.
Rabbeinu Yosef Haim writes in his Sefer Ben Ish Hai (Parashat Chukat), “Although there is no prohibition to interrupt between the various requests of the ‘Harachaman’ section, it is nevertheless prohibited to interrupt with idle chat.” Clearly, the Ben Ish Hai does not mean that there is an actual prohibition to speak idle chat between the various passages, for as we have explained, the basis of this section is merely a custom. Nevertheless, it is certainly improper to interrupt with idle chat while fulfilling a long-standing custom and requesting various things from Hashem and this borders on a prohibition. This is why the Ben Ish Hai uses the word “prohibited” in this context although this is not an actual prohibition.
Similarly, Maran zt”l writes in his Halichot Olam (Volume 2, page 74) that it is preferable and worthy not to interrupt in the middle of the “Harachaman” texts unnecessarily. (Nevertheless, if there is a necessity for one to interrupt in the middle, such as to calm a crying baby and the like, one may speak somewhat between the various “Harachaman” texts.) Certainly, one may interrupt between the various “Harachaman” passages to answer “Amen” or “Kadosh, Kadosh, Kadosh” and the like.
Maran zt”l adds that when necessary, one may stand up in the middle of reciting the “Harachaman” passages and finish reciting them somewhere else, even while standing, for this section need not be said while seated like the rest of Birkat Hamazon.