1. The Hebrew and the Canaan or Phoenician languages have a very great resemblance, and are thought to be but differing dialects of one and the same tongue, as the learned prove by a multitude of words, which are common to both of them. Or,
2. Some of the Hebrews had either out of curiosity, or by Joshua’s order and direction, learnt that language for this or other such like occasions.
Your terror, i.e. the dread of you. See Exo_23:27 34:24 Deu_11:25Deu_28:7.