Thou shalt not see a fierce people, a people of a deeper speech than thou canst perceive; of a stammering tongue, that thou canst not understand.
Thou shalt not see a fierce people - The Assyrians shall not be allowed to enter Jerusalem (2 Kings 19:32). Or, Thou shalt not any longer see fierce enemies threatening thee as previously: such as the Assyrians, Romans, and the last antichristian host that is yet to assail Jerusalem (Deuteronomy 28:49-50; Jeremiah 5:15; Zechariah 14:2).
A people of a deeper speech than thou canst perceive - i:e., of unintelligible language.
Of a stammering tongue - foreign, barbarous. The Assyrian tongue differed only in dialect from the Hebrew; but in the Assyrian levies were many of non-Semitic race and language, as the Medes, Elamites, etc. (note, Isaiah 28:11.)