Yiddish gave Hebrew its emotional register, the warmth, the irony, the catastrophizing, the love language. Modern Hebrew without Yiddish would feel like a Roman general giving a speech. With Yiddish, it becomes a Jewish grandmother kvetching with love. This lesson walks the spectrum from heartbreak to delight.
Cultural note, Yiddish has dozens of words for grief and worry. Hebrew has fewer. When an Israeli wants to express layered emotion, pain wrapped in irony wrapped in love, they reach for Yiddish. Comedians especially. Listen to Israeli stand-up: the punchlines are Hebrew, the soul is Yiddish.