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.
人类可以发出2000多种不同的声音，从常见的“m”和“a”到一些南部非洲语言罕见的咔嗒声。但为什么某些声音比其他声音更常见呢？一项为期五年的突破性研究表明，与饮食相关的人类咬合变化导致了新的语音，目前世界上一半的语言都有这种新语音。
More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals, such as "f" and "y", 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·霍克特指出，唇齿音，比如“f”和“y”，在吃较软食物的群体语言中更为常见。现在，由瑞士苏黎世大学的Damián Blasi领导的一个研究小组已经发现了这种趋势如何变化以及出现的原因。
They discovered that the upper and lower front teeth of ancient human adults were aligned, 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, making it easier to produce such sounds.
他们发现古代成人的上下门牙是对齐的，下唇与上齿接触形成唇齿音的过程变得很难。后来，我们的下巴变成了上包齿结构，发出这样的声音更容易。
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，这种咬合变化与新石器时代农业的发展有关。此时食物变得更容易咀嚼。颌骨不需要做那么多的工作，所以也不会长得那么大。
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.
对语言数据库的分析还证实，新石器时代之后，世界语言的声音发生了全球变化，“f”和“v”的使用在过去几千年中显著增加。这些声音在今天许多狩猎采集者的语言中仍未找到。
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.
这项研究推翻了一种流行的观点，即人类在大约30万年前进化时，所有的语音都存在。研究小组成员史蒂文·莫兰说：“自人类出现以来，我们使用的语音并不一定保持稳定，我们今天发现的各种语音是生物变化和文化进化等复杂相互作用的产物”。
