23. Language

TL;DR

Human language differs from most animal calls through displacement, arbitrariness, recursion, and other cognitive structures that extend communication beyond immediate emotion. Across roughly 6,000 human languages, shared features include semanticity, embedded clauses, meta communication, and motherese. American Sign Language further shows that language is not dependent on speech organs, making the evidence behind these distinctions worth reading on for.

Transcript

[MUSIC PLAYING] Stanford University. Let's get started. We switch to our next subject, where the overall plan could be summarized like that, as you well know by now-- looking at the language, looking at the biological roots of the interactions with the environment, all the deal that we have under our belts by now. Same strategy as usual, starting ... Read More

Key Insights

• Semanticity is the property by which every language buckets an infinite continuum of possible vocal sounds into discrete units of meaning. As Marc Hauser and Noam Chomsky noted, you can generate an infinite number of words but never 6.5 words, because the buckets are discrete and partial words do not exist.
• Recursion, an older term for which is generativity, means every language pairs a finite vocabulary with an infinite set of combinations. Take the longest sentence in history and prefix it with 'Bill said that,' then 'Jane said that Bill said that,' and the generativity never terminates.
• Displacement is the human capacity to talk about the past, the future, the other side of the planet, and topics emotionally distant from the speaker. The overwhelming majority of animal communication instead conveys immediate emotional states: I am upset, afraid, hungry, angry.
• Arbitrariness means the signal has no inherent tie to its message. An animal signaling terror screams or emotes loudly, whereas a human can say 'I am feeling a deeply corrosive sense of disquietude,' and no visual property of a word's letters reveals its meaning.
• Meta communication is the universal ability of every language to talk about language itself. Extreme institutional versions include the French body that rules on which foreign words may become French, and Gallaudet College in Washington DC, where sign language elders decide on new ASL words.
• Motherese, or baby talk, appears in every language and its practitioners: a high-pitched voice emphasizing melodic and vowel aspects, repeated phrases, and close focus on the baby's face. It resembles how people speak to pets, except pet-directed speech lacks the slow, clear articulation.
• The field's dominant view is that language is overwhelmingly about cognition and conceptual structure rather than the motoric generation and reception of sound. The strongest evidence comes from sign languages, which show subtle deep properties similar to spoken language while using completely different brain systems.
• Deaf babies learning American Sign Language begin babbling in signs at roughly the same age, around nine months, that hearing infants babble vocally, and often just before sleep. The developmental rule is to practice fragments of whatever communicative system the infant is exposed to.
• Native ASL signers who have a stroke develop the same categories of communication disorders that speaking individuals do, and these are coded for in very similar parts of the brain. This convergence indicates that damage disrupts language itself, not the motor channel used to express it.
• Prosody covers everything communicated outside the words: tone, facial expression, hand gestures, and body posture. It exists in ASL too, where a signer describing a conversation between two people subtly shifts body position when switching speakers, exactly as spoken-language users do.

Questions & Answers

Q: What makes human language different from animal calls?

Human language supports displacement, allowing people to discuss the past, future, distant places, and emotionally remote subjects such as chess strategies. Most animal communication instead conveys immediate emotional states such as fear, anger, or hunger. Human language is also arbitrary, meaning the form of a signal does not inherently resemble its message.

Q: What features are universal across human languages?

Across roughly 6,000 human languages, Sapolsky identifies semanticity, embedded clauses, recursion, displacement, arbitrariness, meta communication, and motherese. These features let people form discrete units of meaning, build complex statements, discuss distant subjects, and communicate about language itself.

Q: What is semanticity in human language?

Semanticity is the division of an infinite continuum of possible sounds into discrete units of meaning. As Marc Hauser and Noam Chomsky illustrate, people can generate an infinite number of words but cannot generate 6.5 words because partial words do not exist as meaningful buckets.

Q: What is recursion in language?

Recursion, also called generativity, allows a language with a finite number of words to produce an infinite number of combinations. Any sentence can be extended by adding “Bill said that,” followed by another layer such as “Jane said that Bill said that,” without a fixed endpoint.

Q: What does displacement mean in language?

Displacement is the ability to communicate about things removed from the speaker’s immediate situation or emotion. Humans can discuss the past, future, the other side of the planet, or subjects such as chess strategies, while the overwhelming majority of animal communication concerns immediate emotional states.

Q: What does arbitrariness mean in human language?

Arbitrariness means that a linguistic signal has no inherent connection to its message. A terrified animal typically produces something resembling a scream, but a human can calmly describe a “deeply corrosive sense of disquietude.” The appearance of a written word likewise does not reveal its meaning.

Q: Why does American Sign Language show that language is cognitive rather than dependent on speech?

American Sign Language displays deep properties also found in spoken language despite not relying on lips, the larynx, or the throat. Deaf infants babble in signs at around nine months, native signers can develop comparable communication disorders after strokes, and ASL carries prosody and accents. Signing to a deaf native signer also activates the auditory cortex.

Q: How does prosody appear in American Sign Language?

Prosody includes information conveyed beyond words, such as facial expression, gestures, tone, and body posture. In ASL, a signer recounting a conversation can subtly shift body position when changing speakers. That movement reinforces who is speaking just as prosody does in spoken communication.

Summary

This video explores the neurobiology and acquisition of language. It discusses the different brain regions involved in language production and comprehension, such as Broca's and Wernicke's areas, as well as the subcortical regions and limbic system. It also touches on the lateralization of language in the left hemisphere of the brain and the connection between language and emotions. The video highlights the similarities between human and primate brain structure and language abilities.

Questions & Answers

Q: What are some of the universal features of human language?

Some universal features of human language include semanticity, the ability to break sounds into meaningful units, embedded clauses, recursion, displacement, arbitrariness, meta-communication, and the use of motherese or baby talk.

Q: How does the neurobiology of language differ between spoken language and sign language?

While spoken language involves areas related to lips, larynx, and throat, sign language activates similar regions in the brain despite not using sound. Sign languages like American Sign Language (ASL) show activation in motor regions involved in producing and comprehending language, as well as connectivity between these regions and areas typically associated with spoken language.

Q: How does damage to specific brain regions affect language production and comprehension?

Damage to Broca's area can result in a production aphasia where individuals struggle to generate meaningful words and messages. Damage to Wernicke's area can lead to a comprehension aphasia where individuals have difficulty understanding spoken language. The arcuate fasciculus, which connects these areas, plays a role in connecting comprehension to production. Damage to the right hemisphere and limbic system can affect prosody and emotional aspects of language.

Q: Is language production purely a motor function?

No, language production is not solely about motor functions. While there are regions involved in motor movements related to speech and signing, language is deeply intertwined with cognitive and emotional processes. This is evident in the connection between language and limbic areas involved in emotions, facial expressions, and prosody.

Q: How does language lateralization differ between humans and other primate species?

While language lateralization is most pronounced in humans, studies show some level of lateralization in other primate species as well. Monkeys and apes exhibit cortical thickening in regions similar to Broca's area, preferential activation of the left hemisphere during vocalizations, and connections between language regions and facial muscle groups. However, the extent of lateralization is less pronounced compared to humans.

Q: What are some of the debates in the field of language acquisition?

One major debate in the field of language acquisition revolves around the influence of behaviorism and nativism. B.F. Skinner, a behaviorist, emphasized the role of environmental factors in language learning, while Noam Chomsky, a nativist, argued for innate language abilities and a Universal Grammar. This debate has shaped the understanding of how language develops in early life.

Summary & Key Takeaways

• Robert Sapolsky opens the language lecture by applying the course's standard strategy: start with the behavior itself, then work backward toward biological roots and interactions with the environment. He also revisits the previous lecture on complexity, explaining that cortical wiring is itself a solution to the traveling salesman problem, achieved through the brain's equivalent of swarm intelligence.

• The lecture catalogs universals shared by all roughly 6,000 human languages: semanticity, embedded clauses, recursion or generativity, displacement, arbitrariness between signal and message, meta communication, and motherese. Recursion means every language has a finite number of words but an infinite number of possible combinations, demonstrated by prefixing any sentence with 'Bill said that' indefinitely.

• American Sign Language provides the strongest evidence that language lives in conceptual structure rather than the motor acts of speech. Deaf infants babble in sign at the same age hearing infants babble aloud, native signers who have strokes develop the same categories of communication disorders, sign languages carry prosody, accents appear in ASL, and signing activates auditory cortex.