まして (let alone)

Don't even whisper. Speaking loudly is absolutely out of the question, let alone that.

I couldn't afford a bicycle. Let alone a car.

She can't speak English — let alone French, that's out of the question.

She can speak French — let alone English.

She speaks French — English goes without saying.

She can speak Spanish — let alone English, that goes without saying.

She can speak French — let alone English.

He's good at French. English even more so.