四个月英语是 "four months"。

关于来源，"four" 是由古英语 "fēower" 变来的，"month" 来自古法语 "montha" 或拉丁语 "mensis"，表示 "moon" 或 "period of the moon"。

下面是一些例句：

I've been learning English for four months.

It's been four months since we last saw each other.

The baby is four months old.

We have a four-month contract.