Rebecca: Are you speaking human language?

你是在说人类的语言吗？

Here of course he is talking about human language.

当然这里是讲人类的语言。

What are the design features of human language?

人类语言的甄别性特征是什么？

But are the rules of grammar unique to human language?

但是不是只有人类语言讲究语法规则？

A basic property of human language is its creative aspect.

创造性是人类语言的一个基本属性。