一语成谶

他随口来了句：“这飞机该不会掉吧。”
结果真出事了。纯纯的一语成谶。
He joked, "This plane isn't going to crash, right?" It did. A prophecy he never meant to fulfill.

别瞎说，一语成谶就麻烦了！
Don't jinx it!

怕什么来什么。
Spoke too soon, and I was right.

戏言成真，这就是一语成谶吧。
A casual word turned into an unintended prophecy.