Whale Songs Obey Basic Rules of Human Languages
For all the world's linguistic diversity, human languages still obey some universal patterns. These run even deeper than grammar and syntax; they're rooted in statistical laws that predict how frequently we use certain words and how long those words tend to be. Think of them as built-in guardrails to keep language easy to learn and use.
尽管世界上的语言多种多样，但人类语言仍然遵循一些普遍的特性。这些特性甚至比语法和句法更为根本；它们植根于统计规律之中，这些规律能够预测我们使用某些词汇的频率以及这些词汇的通常长度。可以把它们想象成内置于语言中的护栏，让语言更容易学习和使用。
And now scientists have found some of the same patterns in whale vocalisations. Two new studies published this week show that, despite the vast evolutionary distance between us, humans and whales have converged on similar solutions to the problem of communicating through sound.“It strengthens the view that we should be thinking about human language not as a completely different phenomenon from other communication systems but instead think about what it shares with them,” says Inbal Arnon, a professor of psychology at the Hebrew University of Jerusalem and a co-author of one of the studies.
如今，科学家们在鲸鱼的声音中发现了某些相似的模式。本周发表的两项新研究表明，尽管人类与鲸鱼在进化历程上相隔甚远，但双方在通过声音进行交流方面，却找到了相似的解决之道。耶路撒冷希伯来大学心理学教授、其中一项研究的合著者因巴尔·阿农表示：“这强化了一种观点，即我们不应该将人类语言视为与其他交流系统完全不同的现象，而应该思考它与其他交流系统有什么共同点。”
Arnon and her colleagues, whose paper was published on Thursday in Science, analysed eight years of humpback whale song recordings from New Caledonia in the South Pacific—and found that they closely adhered to a principle called Zipf's law of frequency. This mathematical-power law, a hallmark of human language, is observed in word-use frequencies: the most common word in any language shows up twice as often as the second most common, three times as often as the third most common, and so on.
阿农及其同事的论文于周四在《科学》上发表。他们分析了南太平洋新喀里多尼亚长达八年的座头鲸歌声录音，发现这些歌声高度契合齐夫频率定律。研究显示，这一幂律分布作为人类语言的典型特征，具体体现在词汇使用频率上：在任何语言中，最常见词汇的出现频率是次常见词汇的两倍，是第三常见词汇的三倍，依此类推。
But before they could analyse the recordings, the researchers had to identify the segments that were analogous to words (though, importantly, without semantic meaning) in a stream of otherworldly grunts, shrieks and moans. They found themselves in the same predicament as a newborn baby, so naturally, that's where they turned for guidance. Human infants “get this continuous acoustic signal,” Arnon says, “and they have to figure out where the words are.”
然而，在分析这些录音之前，研究人员需从一系列非同寻常的咕噜声、尖叫声和呻吟声中，识别出类似于人类语言中的词汇单元的片段（尽管这些片段本身并无实际语义）。他们发现自己与新生儿面临着同样的认知挑战——于是，很自然地，他们开始寻求方法论参考。人类婴儿“获取的是连续的声学信号流”，阿农说道，“他们必须从中分辨出各个词汇单元的位置。”
A baby's strategy is simple: listen for unexpected combinations of sounds in adult speech. Whenever you identify one, you've probably located a boundary between words because those uncommon transitions are less likely to occur within words.
婴儿的策略很简单：留意成人话语中非预期的音素组合。一旦识别出这样的组合，很可能就找到了单词间的分界处，因为这些不常见的音素过渡在单词内部极少出现。
Incredibly, humpbacks may be using the same approach. When the researchers segmented whale songs based on these “transitional probabilities”—just as a human infant would—they fit Zipf's law of frequency like a glove. On the other hand, 1,000 arbitrarily shuffled elements of the data came nowhere near a match, strongly suggesting the transitional probability results weren't a product of random chance.“We were all dumbfounded,” says co-author Ellen Garland, a whale song expert at the University of St. Andrews in Scotland. “There was the possibility of discovering these same structures. Did we think we would? Hell no.”
令人难以置信的是，座头鲸可能也在使用同样的方法。当研究人员像婴儿分析话语般，基于音段过渡概率划分座头鲸歌声时，发现其与齐夫频率定律高度吻合。另一方面，将1000个数据元素随机重排后完全无法匹配，实验结果充分说明音段过渡概率的结果并非随机现象。“我们有可能发现这些相同的结构，但完全没料到会这样。”苏格兰圣安德鲁斯大学的座头鲸歌声专家、论文合著者艾伦·加兰表示，“我们都惊呆了。”
Why would the same communicative behaviours evolve independently in whales and humans, whose last common ancestor was a shrewlike creature that lived roughly 100 million years ago? Well, distribution of words according to Zipf's law of frequency, or Zipfian distribution, seems to help infantsgrasp language. “When things are organised that way in your input, you're going to learn them better,” says Simon Kirby, a cognitive scientist at the University of Edinburgh and a co-author of the new Science paper.
为什么相同的交流行为会在鲸鱼和人类身上独立演化？要知道，人类与鲸鱼的最后一个共同祖先，是生活在约1亿年前的鼩鼱类祖先。原来，依据齐夫频率定律（又称齐夫分布）来组织词汇，似乎有助于婴儿掌握语言。爱丁堡大学的认知科学家、《科学》期刊新论文的合著者西蒙·柯比表示：“当输入信息呈现这种组织方式时，学习效率将显著提升。”
In other words, the structure of language is largely a product of how it gets passed from one generation to the next. So the team reasoned that Zipf's law of frequency might appear not just in humans but also anywhere else sequential vocal signals are culturally learned (transmitted from one individual to another). That group includes what Kirby calls “a strange, ragtag bunch of species,” including songbirds, bats, nonhuman primates, elephants, seals, dolphins and whales. Pretty much all other animals that communicate vocally—from dogs to frogs to fish—are believed to do so through signals that are genetically programmed, not learned.
换句话说，语言的结构很大程度上取决于它如何代代相传。因此，研究团队推断，齐夫频率定律或许不仅存在于人类语言中，还可能出现在其他存在通过文化习得（个体间传递）的序列声学信号的地方。这一群体被科比称为“一组形态各异、奇形怪状的物种”，包括鸣禽、蝙蝠、非人类灵长类动物、大象、海豹、海豚和鲸鱼。几乎所有其他依靠声音交流的动物，涵盖犬类、蛙类至鱼类，都被认为是通过基因预设的信号进行交流，而非通过学习。
We now know that whales, at least, share a key ingredient of our own communication system, a finding that fits with the growing attitude among scientists that we aren't as unique as we once thought. Rather, our linguistic capacity rests on a smorgasbord of physical and cognitive traits, many of them spread throughout the animal kingdom.
我们现在知道，鲸鱼至少具备我们自身交流系统的核心机制。这一发现与科学家们逐渐形成的观点相契合，即我们并不像曾经认为的那样独特。相反，我们的语言能力建立在多元的生理与认知特质组合的基础之上，其中许多特征在动物界广泛存在。
In a separate paper published in Science Advances on Wednesday, Mason Youngblood, a postdoctoral fellow at Stony Brook University, found evidence of two more such traits in whale vocalisations: One was the brevity law, which, when applied to human language, states that the more common a word is, the shorter it tends to be, and vice versa. The other was Menzerath's law, which says that the longer a linguistic construct (such as a sentence) is, the shorter its constituent parts (such as a sentence's clauses) will be.
在周三发表于《科学进展》的另一篇论文中，纽约州立大学石溪分校博士后梅森·扬布拉德在鲸歌中发现了两种新的人类语言特征：其一是简短法则，该法则表明在人类语言中，词频越高，词长越短，反之亦然；其二是门泽拉特定律，即语言结构（如句子）越长，其构成单元（如从句）越短。
Both patterns were especially strong in humpback song, and both showed up in various other species as well. These laws are all about efficiency. They describe how animals “maximise the amount of information they convey in the least amount of time and with the least amount of energy,” Youngblood says.
这两种模式在座头鲸歌声中尤为显著，且广泛存在于其他物种。扬布拉德指出，这些法则均体现了语言效率原则：“它们揭示了动物如何以最小的时间与能量成本，实现信息传递量的最大化。”
As tempting as the comparisons with human language may be, the researchers caution against reading too much into these parallels. “Whale song is not a language,” Garland says flatly, noting that most experts agree that the animals' “words” don't carry semantic meaning. (Neither does music, for that matter—yet Zipf’s law of frequency appears there, too.)
尽管类比人类语言颇具吸引力，但研究人员警告勿过度解读此类相似性。“鲸歌不具备完整语言系统特征，”加兰明确指出。他强调，多数专家认为动物发声单元缺乏语义编码（同理，音乐虽无明确语义，却同样遵循齐夫频率定律）。
As far as the similarities go, though, they are striking. Luke Rendell, a biologist at the University of St. Andrews, who was not involved with either study, believes these findings could be “telling us something kind of profound about how evolution can either converge at or, perhaps, be constrained to certain types of learning.” That is, they could be informing us about the range of possibilities for complex communication in any species.
然而，这些相似性尤为显著。未参与此两项研究的圣安德鲁斯大学生物学家卢克·伦德尔认为，这些发现可能“揭示了进化如何趋同于特定学习类型，或受其限制”。换言之，它们有助于我们理解任意物种复杂交流能力的潜在边界。
By the same token, Kirby suggests that Zipf's law of frequency (and perhaps other linguistic laws) could be “a kind of fingerprint of these culturally evolved systems,” present wherever animals have crossed the threshold of cultural learning. “It's probably a very fundamental feature of the organisation of cognitive systems,” he adds.
出于同样逻辑，柯比提出，齐夫频率定律（及其他语言定律）可能是文化进化系统的特征性标识，只要动物突破文化学习临界点，该定律便会显现。“这或许反映了认知系统组织的核心特征，”他补充道。
重点词汇
linguistic adj.语言的
syntax n.句法
predict v.预测
vocalisation n.发声
evolutionary adj.进化的；演变的
analogous adj. 相似的；可类比的
predicament n. 尴尬的处境
arbitrarily adv. 任意地；随意地
boundary n. 边界；界限；分界线
grasp v. 抓住；握紧
infant n. 婴儿；婴幼儿
ingredient n. 成分；原料
semantic adj. 语义的
converge v. 汇聚；会合
往期回顾
文章来源 | Cody Cottier: Whale Songs Obey Basic Rules of Human Languages
图片来源| Unsplash
译者 | 马谢尔
译审 | 王春渝
复审 | 李小辉
执行编辑 | 马谢尔
审核编辑 | 王春渝
