relate to this narrower definition.

符合这个狭隘的定义呢
So we could ask,

我们可以发问
in this narrow sense, what properties do languages have

从狭义上说语言拥有何种特性
and then go on to ask,

然后我们可以接着发问
in a broader sense,

从广义上说
what other communicative systems also possess those properties.

哪些其他的交流系统也同样拥有那些特性
Well, some things are obvious about language

有些关于语言的知识非常明显
so here are some; here are the questions we will ask.

这是我们将会提到的的一些问题
This will frame our discussion today.

我们今天就主要来讨论这些问题
We'll first go over some basic facts about language.

我们将首先温习一些语言的基本事实
We'll talk about what languages share,

我们将会谈及各种语言的共性
we'll talk about how language develops,

谈及语言的发展