Prometheus had been vaguely aware of what was going on, and his attention abruptly snaps into focus on the ongoing conversation. And he immediately jumps in before Telamon can pick up the recitation again, although only does a couple of lines, more to show he's there and listening and glad. (Historical literature in general had never really been his thing, but it made Telamon so happy.)
He notices Daedalus, and sends a quiet greeting, before splitting his attention between his decryption work and the reciting.