and writing the background for Family Album,U.S.A.--
为Family Album,U.S.A.撰写背景说明的年轻人
is as the proportion of the total vocabulary of his mother tongue against those words of his own baby talk that are taken up into the vernacular of his family.
就好像他本国语言的总词汇量和自己咿呀学语时他家庭所接纳的他的词汇量之比。