Monkeys have the vocal¹ tracts³ to produce human speech sounds, but what they lack is a speech-ready brain, a new study has found.

据一项最新研究发现，猴子的声道可以发出人类语言的声音，但是它们缺少一个会说话的大脑。

The study, conducted by researchers from the U.S. and Europe and published this week in the U.S. journal Science Advances, used X-ray video to see within the mouth and throat of macaque monkeys induced to vocalize, eat food, or make facial expressions.

这份研究由美国和欧洲的研究者们联合进行、发表在本周的美国杂志《科学进展》上，在猕猴发出声音、进食和做出面部表情时，他们使用X射线来观察它们嘴巴和喉咙内部。

The scientists then used these data to build a computer model of a monkey vocal tract², allowing them to answer the question "what would monkey speech sound like, if a human brain were in control?"

科学家们随后用这些数据建立了一个猴子声道的电脑模型，从而使得他们回答这一问题--“如果猴子长了人脑，那么它们的语言是什么样的？”

The results showed that monkeys could easily produce many different sounds, enough to produce thousands of distinct words.

结果表明，猴子可以轻松地发出许多不同的声音，足以产生上万个不同的词汇。

For example, monkeys could produce comprehensible vowel⁴ sounds -- and even full sentences -- with their vocal tracts if they had the neural⁵ ability to speak.

举例来说，如果猕猴真的具有神经功能的语言能力，它们可以用自己的声道说出可理解的元音--甚至是完整的句子。

The researchers noted⁶, however, that while monkeys would be understandable to the human ear, they would not sound precisely⁷ like humans.

不过研究者们指出，虽然人类可以理解猕猴说的话，但是它们的声音却和人类不大一样。

Therefore, the researchers concluded that previous research -- largely based on plaster casts made from the vocal tracts of a monkey cadaver⁸ -- underestimates primate⁹ vocal abilities and that evolution of human speech capabilities¹⁰ required neural changes rather than an adaptation of vocal anatomy¹¹.

因此研究者们作出结论，之前的研究（很大程度上基于一只死亡猴子声道的石膏模型）低估了灵长类动物的发声能力，而人类语言能力进化需要的是神经的改变，而不是声道生理构造的改变。

"Now nobody can say that it's something about the vocal anatomy that keeps monkeys from being able to speak -- it has to be something in the brain," said Asif Ghazanfar, a professor of psychology¹² at the Princeton University and one of the study leaders.

该项研究领导者之一、普林斯顿大学心理学教授阿西夫表示：“现在没人说猴子不能说话是因为声道生理构造和人类不同了--而是它们大脑里的东西和人类不同。”