、。
Excuse me, sir/ma'am — could you please keep it down a little?
Literal
Customer, a-little-more quietly.
A service-industry phrase where the verb is entirely omitted — the listener fills in してください or お願いします. お客様 is the keigo form of 'customer,' with the honorific prefix お and the respectful suffix 様. お静かに uses the honorific お + adjective stem + に, a polite adverbial construction functioning as a gentle indirect request. The absence of an explicit verb makes it softer than a direct command — a hallmark of Japanese indirect communication.