Not all sounds made by animals serve as language, and we have only to turn to that extraordinary discovery of echo-location in bats to see a case in which the voice plays a strictly utilitarian role.

动物发出的声音不一定都是语言，如果我们看看蝙蝠利用回声定位，就能看到一个例子：声音在其中扮演着非常重要的角色。