You must develop the muscles of your speech organs to produce unfamiliar sounds.
所以你必须训练和发展你的发音器官(声带、舌、口、鼻腔等)的肌肉,以便发出陌生的(另外一种语言)声音。
To get a full appreciation of what this means we must turn first to some recent human inventions.
要透彻理解这句话的意义,我们应先回顾一下人类最近的几项发明。