The author compares the development of language as a rolling ball, and visually explains the status and function of newly emerged elements in the rolling forms.

• 作者将语言的发展比作一个向前不断滚动前进的球体，形象说明了新生语言成分在语言整体发展的过程中所处的语言地位及其对语言整体体系发展的影响和作用。