How do you say second youngest brother in Japanese?

There isn't a single perfect translation for "second youngest brother" in Japanese, as the phrasing depends on the context and the speaker's relationship to the brothers. However, here are a few options:

* 次男 (jinan): This literally means "second son." This is the most straightforward and common way to refer to the second youngest brother if you have more than two brothers. It implies a younger brother who is second from the youngest.

* 末っ子から二番目 (sutekko kara nibanme): This means "second from the youngest." This is a more descriptive phrase and is useful if you want to emphasize the position relative to the youngest. `末っ子 (sutekko)` means the youngest child.

* You could also describe him using his name and a phrase clarifying his birth order, such as:

* [Brother's Name] さんは兄弟の中で二番目に若い ( [Brother's name]-san wa kyōdai no naka de nibanme ni wakai) - "[Brother's Name] is the second youngest in the siblings."

The best option depends on the situation. If you're talking casually amongst family, 次男 (jinan) is perfectly fine. If you need to be more precise or are talking formally, the longer phrases might be better.