Rats can use the rhythm of human language to tell the difference between Dutch and Japanese, researchers in Spain reported.

Their study suggests that animals, especially mammals, evolved some of the skills underlying¹ the use and development of language long before language itself ever evolved, the researchers said.

It is the first time an animal other than a human or monkey has been shown to have this skill.

For their study neuroscientists Juan Toro and colleagues at Barcelona's Scientific Park tested 64 adult male rats.

They used Dutch and Japanese because these languages were used in earlier, similar tests, and because they are very different from one another in use of words, rhythm and structure.

The rats were trained to respond to either Dutch or Japanese using food as a reward.

Then they were separated into four groups -- one that heard each language spoken by a native, one that heard synthesized speech, one that heard sentences read in either language by different speakers and a fourth that heard the languages played backwards².

Rats rewarded for responding to Japanese did not respond to Dutch and rats trained to recognize Dutch did not respond the spoken Japanese.

The rats could not tell apart Japanese or Dutch played backwards.

"Results showed that rats could discriminate³ natural sentences when uttered by a single speaker and not when uttered by different ones, nor could they distinguish⁴ the languages when spoken by different people," the researchers wrote.

Human newborns have the same problem, although tamarins can easily tell languages apart even when spoken by different people, the researchers said.

The study shows "which abilities that humans use for language are shared with other animals, and which are uniquely human. It also suggests what sort of evolutionary⁵ precursors⁶ language might have. 

　　西班牙科学家经研究发现，鼠类可以根据人类语言的特定节奏来区分荷兰语和日语。这也是迄今为止科学界首次发现一般动物而不是人或者猴子具有这种本领。

　　据路透社1月9日报道，研究者在最新一期的美国《实验心理学杂志·动物行为过程》期刊上发表文章指出，这一实验结果显示出动物，特别是哺乳动物早在人类语言形成之前就已经具有了某种使用和开发语言的潜在能力。报告还说，这个在鼠类身上显现出来的本领与成年人、新生婴儿以及南美绢毛猴的情况均具有显著的相似性。

　　西班牙巴塞罗那科学园区的神经学家胡安·托罗利用64只成年雄性鼠进行实验。先以食物奖励的方法训练实验鼠在分别听到日语或荷兰语时作出反应。然后再将实验鼠分成4组：第1组分别听标准的荷兰语和日语；第2组听双语混合语；第3组听不同的扬声器或人用任意两种语言说话；第4组听这两种语言句子的倒放录音。

　　实验结果显示，那些被训练对日语作出反应才受到奖赏的实验鼠，不会对荷兰语作出反应；而那些被训练识别荷兰语的实验鼠，则不会对日语作出反应。另外，两类实验鼠皆不能辨别日语和荷兰语的倒放录音。

　　研究者们还发现，当只有一个扬声器发声时，实验鼠可以分辨出这两种语言中的自然句；如果用不同的扬声器或不同的人说话时，实验鼠则不能区分两种语言的不同。以往的科学实验表明，新生婴儿在语言识别方面也有类似的情况，而绢毛猴的“本领”就显得大多了，因为不管是同一个人还是不同的人说话，它们都能够辨别出来。

　　科学家认为这项研究将有助于进一步探索，人类应用在语言上的能力哪些是与其他动物共享的，哪些是人类独有的，以及在生物进化的过程中，人类语言在正式形成之前到底是什么样子。

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