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improvement (e.g. in skill, ability); advance; progress
communication of opinions of the general populace to those of high rank
日本語がずいぶん上達したね。
Your Japanese has improved a lot.
上達するには練習が必要だよ。
Practice is needed to improve.
ピアノの上達が早くて驚いた。
I was surprised at the fast piano progress.