The history of the Assyrian Empire from about 750 B.C. to the fall of Nineveh when the Babylonians received the kingdom and the subsequent history of the fall of Jerusalem and exile of the Jews until their return at the command of Cyrus the Persian to the second commonwealth is necessary background to understanding Isaiah. Especially important is the sequence of Kings and events from 745 to about 700 B.C. Vocabulary and Sentence Structure Reading the prophets, especially Isaiah, in Hebrew is not like reading a new language when compared to the relatively easy reading of the narrative material of Genesis and the historical books. But a different vocabulary and sentence structure is a part of Isaiah's style. Mystical vision Isaiah says that he received his messages in visions. That would include dreams, trances and mystical voyages.
Extensive alliteration causes confusion even to the careful reader.
Also, visionary repetition of important events three or more times does not indicate three or more events but rather the certainty of the event. The over throw of Satan under the symbol of Leviathan the dragon in chapter 27 is an example. One of the major devices is the use of a play on words. Sometimes it is simply the use of rhyming words or acronyms. At other times words are used that have double meaning.