If a person finished his recitation of the silent Amida and now waits for the Hazzan to begin his repetition, is it permissible for him to study Torah while he waits? For that matter, may he recite Tehillim or sections of the prayer service that he had skipped?
It is worth emphasizing in this context that Halacha strictly forbids speaking during the Hazzan's repetition of the Amida, as one must concentrate on the Hazzan's prayer and respond, "Baruch Hu U'baruch Shemo" and "Amen." This prohibition applies even to prayers and words of Torah. Interestingly enough, the Shulhan Aruch writes about somebody who speaks during the Hazzan's repetition, "Gadol Avono Mi'neso" "His sin is too great to bear." The fact that Maran included such a comment in this context which is very rare in the Shulhan Aruch demonstrates the gravity Halacha affords to the prohibition against speaking during the Hazzan's repetition.
Returning to the question of learning and praying before the Hazzan's repetition, Halacha indeed allows one to learn or pray at this point. Likewise, if one hears Kaddish, Kedusha or a Beracha as he waits for the Hazzan's repetition, he may answer with the appropriate response. It must be noted, however, that one may not engage in idle chatter as he waits for the Hazzan; Rav Haim Palachi (Turkey, 1788-1869) cites this point in the name of the students of the Arizal (Rabbi Yishak Luria, Israel, 1534-1572).
These guidelines apply only to the congregation. The Hazzan himself, however, may not speak as he waits to begin the repetition. He may learn silently, but may not study out loud or recite any verses, prayers and the like. The exception to this rule is when the Hazzan hears Kaddish, Kedusha or a Beracha, in which case he is permitted to answer with the appropriate response. Otherwise, he must remain perfectly silent until he begins the repetition of the Amida.
Summary: If one completes the Amida before the Hazzan, while he waits for the repetition to begin he may study Torah, recite verses or prayers, and respond to Kaddish, Kedusha and Berachot, but he may not engage in idle chatter. The Hazzan himself, however, must remain silent until he begins the repetition, unless he hears Kaddish, Kedusha or Berachot, in which case he may respond. Otherwise, he may only read silently with his eyes, without verbalizing any words.
