Both use babbling to master the control of their vocal apparatus, enabling them to produce complex sounds and vocalizations.

人类和蝙蝠都利用咿呀声来控制发声器官，这令二者有能力发出复杂的声音和语音。

All of the vowel sounds that we make are made in different places of our face, our vocal apparatus, OK?

发元音的时候每个音的位置都会运用到不同的部位。

They are cooing and babbling to practise the use of their vocal apparatus.

他们通过咕咕叫和喋喋不休来练习使用他们的发声器官。