P1:topic: detection of an ancient signal(背景:公认languages cannot be traced very far back in time)
P2A用了一个statistical methods进行history linguistics研究,其他学者认为这个方法得出的结果可以接受
P3A对phonemes进行研究,发现离Africa越远,phoneme越少(e.g. Africa vs. Hawaiian)
P4: the pattern of phonemes( vs. Genetic diversity)表明语言起源于southweatern Africa
P5:他的研究被一项最近的研究支持,他得出phoneme diversity会随着人口增加,但是当小群体脱离大群体的时候,pd会减少
P6:随着距离Africa越远,phoneme diversity的减少伴随着genetic diversity的减少
P7:modern language表明human expansion out of Africa was very rapid at each of stage
108.
[Main Idea] Prior research found it difficult to trace the history of languages. But biologists A found the pattern of phonemes of the laguage, which is similar to the ginetic one.
[Structure]
P1: Most lingustics belive that languages can not be traced far back in time.
P2: Dr. A started to use new methods.
P3: Dr. A found the pattern of phonemes: Fewer phonemes area, father place early humans traveled from Africa to reach it.
P4: The pattern is similar to the genetic one.
P5: Dr. A's study was prompted by a recent study: the number of phonemes change with the number of people who speak the language.
P6: The reduction in phonemic diversity parallels the redutcion in genetic diversity.
P7: Both reductions implies human's rapid expansion.