早める and 急ぐ: moving a planned time earlier and hurrying
Compare bringing a departure plan forward with hurrying preparations, keeping a changed schedule distinct from actual departure.
Moving a planned time earlier
早める, read はやめる, refers here to bringing a planned time forward. 出発の予定を三時から二時に早めました。 says that the departure plan was moved from three o’clock to two.
締め切りを一日早めました。 says that the deadline was brought forward by one day. The day measures the change, not the total work period.
Performing an action in a hurry
急ぐ, read いそぐ, means hurrying. 準備を急いでいます。 says that preparations are being hurried.
急いで歩きました。 says that the person walked in a hurry. Neither a destination nor an arrival time is specified.
A schedule change and the actual action
出発の予定を早めましたが、まだ出発していません。 says that the departure plan was moved earlier, but departure has not yet occurred. The plan changed; the departure remains incomplete.
急いで準備しました。 says that preparations were made in a hurry. A change to the original schedule requires separate wording.
Has departure already occurred in 出発の予定を早めましたが、まだ出発していません。?
Show the answer and why
No. The departure plan was moved earlier, but the sentence also states that departure has not yet occurred.