en_tn_condensed/isa/23/02.md

Be silent, you inhabitants of the coast

Isaiah speaks to the people who live on the coast as if they could hear him. (See: rc://en/ta/man/translate/figs-apostrophe)

Be silent

This is an idiom. Here silence is meant to signal shock and amazement. AT: "Be shocked" (See: rc://en/ta/man/translate/figs-idiom)

of the coast

The "coast" is the land near or around the sea or ocean. Here it refers to the people who live in Phoenicia which borders the Mediterranean sea.

the merchant of Sidon, who travels over the sea, has filled you

Here "merchant" means "many merchants." AT: "the merchants of Sidon, who travel over the sea, have made you rich" (See: rc://en/ta/man/translate/figs-genericnoun)