en_tn/jer/48/30.md

I myself know his arrogant speech

The word "myself" is used to emphasize that Yahweh was the one who knew about Moab's arrogant speech. (See: rc://en/ta/man/jit/figs-rpronouns)

his arrogant speech ... like his deeds

Here "his" refers to Moab which represents the people of Moab. Alternate translation: "their arrogant speech ... like their deeds" (See: rc://en/ta/man/jit/figs-metonymy)

his arrogant speech

The abstract noun "speech" can be stated as a verb. Alternate translation: "that he has spoken arrogantly" or "that he has spoken arrogant words" (See: rc://en/ta/man/jit/figs-abstractnouns)