エレベーターで住んでいる階を聞く会話

How do you politely ask where someone lives in Japanese?

You rarely say bare お住まいですか — it comes with a place, as 〜にお住まいですか (~ ni o-sumai desu ka), a courteous way to ask where someone lives. この辺りにお住まいですか means “Do you live around here?”; 何階にお住まいですか asks “What floor do you live on?” 住まい is a noun for “residence” (from 住む, “to live”), and the honorific お- makes it polite — much softer than the blunt どこに住んでいますか.

The reply in the clip is a floor number: 何階 (nan-gai), “what floor,” answered 二十八階 (“28th floor”). Floors take the counter 階, whose sound shifts — 一階 ikkai, 三階 sangai. That polite お- prefix rides on many words: お名前 (“your name”), お仕事 (“your work”). Reach for お住まい when どこに住んでる？ would feel too direct.