Human speech contains more than 2,000 different sounds, from the common “m”and “a” to the rare clicks of some southern African languages. But why are certain sounds more common than others? A ground-breaking, five-year study shows that diet-related changes in human bite led to new speech sounds that are now found in half the world’s languages.
人类语音包含超过2,000种不同的声音，从常见的“m”和“a”到一些南非语言中罕见的咔嗒声。但为什么有些声音比其他声音更常见呢？一项具有突破性的、为期五年的研究表明，与饮食相关的人类咬合变化导致了新的语音声音的产生，这些声音现在存在于全球一半的语言中。

More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals, such as “f” and “v”, were more common in the languages of societies that ate softer foods. Now a team of researchers led by Damián Blasi at the University of Zurich, Switzerland, has found how and why this trend arose.
30多年前，学者查尔斯·霍克特特（Charles Hockett）注意到，称为labiodentals的语音声音，比如“f”和“v”，在吃软食的社会的语言中更为普遍。如今，由瑞士苏黎世大学的达米安·布拉西（Damián Blasi）领导的研究小组发现了这种趋势是如何产生及原因。

They discovered that the upper and lower front teeth of ancient human adults were aligned (对齐), making it hard to produce labiodentals, which are formed by touching the lower lip to the upper teeth. Later, our jaws changed to an overbite structure (结构), making it easier to produce such sounds.
他们发现古代成年人的上下门牙是对齐的，这使得他们很难发出唇齿音，因为这需要下唇接触上门牙。后来，我们的下颌改变为过度咬合结构，这样更容易发出这种音素。

The team showed that this change in bite was connected with the development of agriculture in the Neolithic period. Food became easier to chew at this point. The jawbone didn’t have to do as much work and so didn’t grow to be so large.
研究小组表明，这种咬合方式的变化与新石器时代农业的发展有关。食物变得更容易咀嚼。下颚不需要那么多工作，因此不会长得那么大。

Analyses of a language database also confirmed that there was a global change in the sound of world languages after the Neolithic age, with the use of “f” and “v” increasing remarkably during the last few thousand years. These sounds are still not found in the languages of many hunter-gatherer people today.
语言数据库的分析还证实，在新石器时代之后，世界语言的音声发生了全球性的变化，过去几千年中，“f”和“v”的使用显著增加。这些音声在许多现代狩猎采集者的语言中仍然无法找到。

This research overturns the popular view that all human speech sounds were present when human beings evolved around 300,000 years ago. “The set of speech sounds we use has not necessarily remained stable since the appearance of human beings, but rather the huge variety of speech sounds that we find today is the product of a complex interplay of things like biological change and cultural evolution,” said Steven Moran, a member of the research team.
这项研究推翻了一个流行观点，即所有人类言语音均在人类大约30万年前进化时就已存在。“我们使用的言语音集并不一定自人类出现以来就保持稳定，而今天我们发现的大量言语音种类是生物变化和文化演化等复杂因素相互作用的产物，”研究团队成员Steven Moran表示。

1. Which aspect of the human speech sound does Damián Blasi’s research focus on?
   A. Its variety.
   B. Its distribution.
   C. Its quantity.
   D. Its development.
   答案：D

2. Why was it difficult for ancient human adults to produce labiodentals?
   A. They had fewer upper teeth than lower teeth.
   B. They could not open and close their lips easily.
   C. Their jaws were not conveniently structured.
   D. Their lower front teeth were not large enough.
   答案：C

3. What is paragraph 5 mainly about?
   A. Supporting evidence for the research results.
   B. Potential application of the research findings.
   C. A further explanation of the research methods.
   D. A reasonable doubt about the research process.
   答案：A

4. What does Steven Moran say about the set of human speech sounds?
   A. It is key to effective communication.
   B. It contributes much to cultural diversity.
   C. It is a complex and dynamic system.
   D. It drives the evolution of human beings.
   答案：C