We already learned that it is forbidden to interrupt by speaking in the middle of Pesukei De-zimra and Shema and its berakhot. However, for an urgent matter, such as to prevent damage or insult, it is permissible to interrupt (see above, 16:14; 15:6). Thus, just as one may interrupt for an important matter, so too one may interrupt to respond to devarim she-bikdusha. Therefore, if one is reciting Pesukei De-zimra or Shema and its berakhot and hears Kaddish, Barkhu, Kedusha, or Modim may answer. However, she is not obligated to stop and respond, as one who is reciting Pesukei De-zimra is already occupied with devarim she-bikdusha, and there is no affront to God’s honor if she continues her prayer. However, if she is surrounded by women who are responding to Kedusha and Modim, it is proper that she stop and answer together with them, because those responses are accompanied by an act (standing with feet together and bowing), and if she would continue sitting, she would appear to be separating herself from the congregation. Once she must interrupt her prayer to stand or bow with them, it is preferable that she answer with them.
The permissibility of interrupting one’s prayer to respond to Kaddish applies only to the central part of Kaddish (that which is recited in the Half-Kaddish). She does not respond to the later additions, for they are not the essence of Kaddish. Likewise, clearly one must not interrupt to respond “Barukh Hu u-varukh shemo,” as this response is mere custom.
Regarding answering “amen” to berakhot, such as the berakhot of Ĥazarat Ha-shatz: While reciting Pesukei De-zimra one may answer, but not while reciting Shema and its berakhot (see Peninei Halakha: Prayer, 14:4 n. 7; 16:5 n. 4). 1
- According to Ashkenazic custom, one may answer “amen” to Ha-Kel Ha-kadosh and Shome’a Tefila while reciting Birkhot Keri’at Shema, for they are on a higher level because they conclude the berakhot of praise and the berakhot of request. According to Sephardic custom, those particular berakhot have the same status as other berakhot, and one does not respond to them. Likewise, Sephardic custom is that one who finishes one of the Birkhot Keri’at Shema before the ĥazan does not answer “amen,” just as he does not respond “amen” to any berakha. Ashkenazic custom is to answer because since it is one of the Birkhot Keri’at Shema, responding to it is not considered an interruption (MB 59: 24-25; Kaf Ha-ĥayim 26, 28). ↩