Hosea 2:1 New English Translation

2 Then you will call^[a] your^[b] brother, “My People” (Ammi)! You will call your sister, “Pity” (Ruhamah)!

Hosea 2:1 tn Heb “Say to….” The imperative אִמְרוּ (ʾim^eru, Qal imperative masculine plural) functions rhetorically, where one verbal form (imperative) substitutes for another (indicative). The imperative is used as a rhetorical device to emphasize the certainty of a future action.
Hosea 2:1 sn The suffixes on the nouns אֲחֵיכֶם (ʾakhekhem, “your brother”) and אֲחוֹתֵיכֶם (ʾakhotekhem, “your sister”) are both plural forms. The brother/sister imagery is being applied to Israel and Judah collectively.

New English Translation (NET)