Reference for Megillah 50:5

קללות וברכות נקרין ומתרגמין פשיטא מהו דתימא ניחוש דלמא פייגא דעתייהו דצבורא קמ"ל

The curses and blessings are both read and translated. This is obvious! What might you have thought? That we should be concerned lest the congregation should become disheartened; therefore it teaches us.

Jastrow