Addressee-switching refers to the literary-linguistic device in the Bible whereby prophets included foreign elements in oracles (ostensibly) directed at foreign nations. To be sure, these texts were heard only by the Israelite consumers of ancient Hebrew literature, but the addition of such foreign elements no doubt added a hint of reality and authenticity to the speeches.
The first to identify this device appears to have been Chaim Rabin (1967:304–305): “It is a feature of First Isaiah’s style that, when speaking of or addressing a foreign nation, h…