UE4: Settings
Installing an older version Click +button and add a new slot in Library tab. Choose an older version from dropdown list for the slot. Switching Languages (Editor Languages) / 言語変更 Editor in Menu > Editor Preferences : 編集 > エディタ環境設定 General/Region & Language : 一般-地域&言語 Internationalization/Editor Language : 国際化/エディタの言語