你家有四口人可以用中文说成「我家有四口人」。这句话的英文翻译是："There are four people in my family." 例句：

I have a wife and two children, so there are four people in my family.

My family consists of my parents, my sister, and me. There are four people in total.

I come from a small family with only four members: my mother, father, brother, and me.