Hosea uses the term "Ephraim" to refer to the entire northern kingdom, although it was also the name of one of the ten tribes. Hosea seems to be speaking of a long-past time, when the northern kingdom was strong and honored, unlike at the present time. (See: [[rc://en/ta/man/translate/figs-synecdoche]])
The missing phrase "among other nations" is understood here. Other nations felt humility in front of the northern kingdom. AT: "there was trembling among other people" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
When the people of Ephraim began worshiping Baal, they grew weak, and their enemies defeated them. Here "died" refers to the nation growing weak. (See: [[rc://en/ta/man/translate/figs-metaphor]])