小哥哥用英语可以翻译为 "little brother"。它的来源是源于中文语言，并且在英语中广泛使用。

例句：

I have an older sister and a little brother.

(我有一个姐姐和一个小哥哥。)

My little brother is very curious and always asking questions.

(我的小哥哥非常好奇，总是会问很多问题。)

Can you please help me with my little brother? He's driving me crazy.

(你能帮我照顾一下我的小哥哥吗？他把我逼疯了。)