Language and Communication Lecture Notes

Fundamental Criteria Defining Human Language

• Communication systems enable information to be transmitted and received between individuals or groups across a variety of modalities.
• While numerous communication systems exist across the animal kingdom (such as the warning growl of a dog, a parrot mimicking human vocal patterns, or the abstract, complex mating song of a bird), most psychologists classify only human communication as true language.
• True language is distinguished from other animal communication systems by three fundamental criteria:
  • Regularity: Language is governed by a systematic framework of rules and grammar. Sentences can be reorganized while retaining their core meaning because an underlying grammatical structure specifies how words functionally relate to one another.
  • Arbitrariness: The acoustic or visual symbols used to represent concepts do not inherently resemble or describe the objects or ideas they signify. For example, the phonological sequence in the English word "cat" bears no intrinsic physical connection to a small, furry feline with whiskers and a tail; if sounds were required to represent physical properties, the same animal would not be identified as "cat" in English and "a angi" in Korean.
  • Productivity: Language possesses an almost limitless capacity to combine discrete words to express an infinite number of novel objects, situations, actions, and thoughts. Infants demonstrate this characteristic by actively generating novel sound and word combinations that they have never been explicitly taught.

Language and Thought: The Sapir-Whorf Hypothesis

• Internal dialogue in a native language frequently shapes thought processes, planning, and self-reflection, demonstrating that while thought and language are not strictly identical, human cognition often takes a linguistic form.
• The Sapir-Whorf Hypothesis (also referred to across literature as the Sapere Wharf or Superior Wharf hypothesis) posits that the specific structure and vocabulary of a language influence or determine how its speakers perceive and experience the physical world.
• Evidence Supporting the Hypothesis:
  • Studies of the Peraja, an isolated hunter-gatherer tribe residing in Brazil, demonstrate linguistic constraints on numerical cognition.
  • The native Peraja language lacks specific numerical terminology beyond three basic counting words: $1$, $2$, and "many".
  • In experimental trials conducted by Peter Gordon of Columbia University, Peraja tribe members were asked to match sets of familiar objects (such as sticks or nuts) laid out by the experimenter.
  • Participants performed accurately when matching groups consisting of $1$ or $2$ items.
  • Performance declined significantly when tested on sets greater than $3$ objects, supporting the strong version of the hypothesis that a lack of fine numerical words impairs fine numerical discrimination.
• Evidence Countering the Hypothesis:
  • Cultural differences in kinship terminology demonstrate that cognitive understanding can exist independently of distinct linguistic labels.
  • In the French language, the single term bell me is used to denote both "mother-in-law" and "stepmother"; despite this shared lexical item, French speakers understand the precise genealogical and interpersonal distinctions between these roles.
  • The Korean language uses highly specific terms for extended family members based on lineage and birth order (e.g., a father's older brother is termed Kunabuji, whereas a mother's older brother is termed Sachun).
  • The English language collapses both of these distinct familial relationships into the single term "uncle"; despite this absence of specialized vocabulary, English speakers fully comprehend the distinct family relationships.
• The degree to which language constrains or directs abstract thought remains an unresolved scientific debate.

Structural Building Blocks: Morphemes, Phonemes, Syntax, and Semantics

• More than $3,000$ active languages exist in the world today, all of which share universal structural features despite employing different words and sound combinations.
• Morphemes:
  • In oral languages, morphemes are the smallest units of sound that convey meaning or grammatical information. In manual or sign languages, morphemes consist of structural units of sign.
  • Morphemes can function as standalone words or combine to create complex words:
    • Single morpheme word: "table" consists of a single morpheme that conveys one unit of meaning.
    • Multi-morpheme compound word: "tablecloth" combines two independent morphemes ("table" and "cloth"), each providing distinct information.
  • Free vs. Bound morphemes:
    • Free morphemes can stand alone as meaningful words (e.g., "table", "cloth").
    • Bound morphemes cannot stand alone and must be appended to other morphemes to convey meaning.
    • Pluralization: In the word "tables", the bound morpheme "-s" attaches to "table" to denote a quantity of more than one.
    • Tense and action markers: In the word "cleaning", the root morpheme "clean" denotes the action, while the bound morpheme "-ing" indicates that the action is actively occurring in the present. Replacing "-ing" with "-ed" ("cleaned") indicates that the action occurred in the past.
  • Linguistic classification of morphemes can be complex and debated in advanced linguistics (e.g., determining the exact morphemic status of words like "butterfly").
• Phonemes:
  • Phonemes are the elementary constituent sounds that make up morphemes; they represent the absolute smallest functional units of language.
  • For example, the single-morpheme word "dog" contains three distinct phonemes: $d$, $o$, and $g$.
  • Each language possesses an approved inventory of usable phonemes and strict phonotactic rules regarding how these sounds can be ordered.
  • Permissible phonological combinations can yield plausible, pronounceable non-words that conform to the rules of a language without carrying semantic meaning (e.g., "quijbo" or "quigibo" in English).
• Syntax (Grammar):
  • Syntax refers to the systematic set of structural rules governing how words and phrases are arranged to construct grammatically valid sentences, directly providing the "regularity" of a language.
  • Syntactic conventions vary across cultures:
    • French assigns grammatical gender to all inanimate objects and requires prepositions and articles (such as "the" or "my") to match the gender of the noun.
    • English does not assign grammatical gender to inanimate nouns (a "table" has no gender in English, unlike in French), reserving gendered pronouns primarily for living organisms ("he" or "she").
  • Native speakers exhibit high processing fluency with native syntax, applying complex grammatical rules automatically while often finding it difficult to articulate those formal rules explicitly.
• Semantics:
  • Semantics refers specifically to the meaning of individual words and sentences, distinct from their structural arrangement.
  • A sentence can exhibit flawless syntactic structure while completely lacking semantic coherence.
  • Classic illustrative example: The novel construction "the colorless green ideas, sleep furiously beside the quigibo" perfectly satisfies English syntactic rules, yet conveys zero semantic meaning.

Developmental Milestones of Speech Perception and Production

• Human infants possess basic physical needs (hunger, thirst, fatigue, boredom, physical discomfort) but lack initial verbal capacity, communicating these states exclusively through crying.
• Systematic Language Acquisition Timeline:
  • Early infancy: Development of foundational social-communicative behaviors, including responding to human presence and social smiling.
  • Babbling stage: Production of drawn-out sound sequences combining vowels and consonants. Babbling incorporates native prosodic elements, rhythm, and inflection, mimicking the intonation of questions or conversational turns. Over time, infants narrow their vocalizations to repeat sound combinations specific to their ambient linguistic environment.
  • Language explosion: Occurring between approximately $1.2$ and $6$ years of age, characterized by an exceptionally rapid expansion of vocabulary, mastery of primary language mechanics, and increasing syntactical complexity.
• Speech Segmentation:
  • Unfamiliar spoken languages often give the illusion of being spoken at extreme speeds due to the listener's inability to segment a continuous acoustic speech stream into discrete word units.
  • Newman and colleagues examined the relationship between early speech segmentation and later linguistic competence:
    • Infants aged $7.5$ to $12$ months were familiarized with a target word (e.g., "dog").
    • Infants were presented with spoken stories to evaluate whether they could detect and segment the familiar target word within continuous speech.
    • At $2$ years of age ($24$ months), the same children were assessed via a parental checklist measuring expressive vocabulary (the total count of words a child can actively produce).
    • Results demonstrated a strong positive correlation: infants with superior speech segmentation abilities at $7.5$ to $12$ months had significantly larger expressive vocabularies at age $2$, whereas poor segmenters developed smaller expressive vocabularies.
    • Clinical utility: Speech segmentation tests offer an avenue for infant diagnostic screening to identify early developmental language deficits and direct clinical interventions.
• Universal Phonemic Sensitivity:
  • Young infants possess an innate capacity to discriminate between virtually all human phonetic contrasts, including those absent from their native language environment.
  • Adult speakers exhibit perceptual narrowing:
    • Japanese and Korean adults struggle to differentiate the English $r$ and $l$ phonemes (as in "radio" versus "ladio"), whereas Japanese and Korean infants discriminate them effortlessly.
    • Native English-speaking adults struggle to perceive the distinction between the Korean "Ja" and "Jada" phonemes (which differentiate the word for "to sleep" from the word "to be salty"), hearing them as identical, whereas Korean speakers readily distinguish them.
• The Head-Turn Preference Procedure:
  • A specialized behavioral paradigm used to test phonemic discrimination in pre-verbal infants.
  • Training Phase: An infant is conditioned to turn their head toward an audio speaker when a change in phoneme occurs, receiving visual reinforcement (such as an activated toy doll) upon a correct turn.
  • Testing/Habituation Phase: The infant is habituated to a repeating phoneme until their interest wanes (indicated by a decrease in looking behavior). A novel test phoneme is introduced. A head turn toward the speaker confirms that the infant discriminates the acoustic difference between the two phonemes.
• Developmental Decline of Universal Sensitivity:
  • In cross-linguistic studies comparing English-speaking adults, infants from English-speaking households, and Hindi-speaking adults on Hindi phonemic contrasts not present in English:
    • English-speaking adults perform the poorest.
    • English-learning infants perform nearly as well as native Hindi-speaking adults.
  • This universal phonemic sensitivity declines sharply by the end of the first year of life ($1$ year of age), after which infants lose the ability to differentiate non-native phonemes.
  • Adults exposed to a second language for $10$ months can improve general comprehension and production, but require prolonged, intensive practice to discriminate fine phonemic contrasts, contrasting with the effortless mastery achieved during early childhood development.

Theories of Language Acquisition: Social Learning vs. Innate Mechanisms

• Social Learning Theory:
  • Posits that language acquisition is driven by a combination of observational learning, imitation of adult models, and instrumental (operant) conditioning.
  • Reinforcement mechanism: When a babbling infant accidentally utters an appropriate phoneme sequence (e.g., "mama"), caregivers immediately provide positive reinforcement via smiles, vocal praise, and attention, reinforcing the verbal behavior.
  • Evidence from severe deprivation:
    • The case of Genie: A child isolated in extreme abuse from early childhood until age $13$, kept locked in a small room with virtually no human interaction or verbal exposure.
    • Upon her rescue at age $13$, Genie possessed virtually no communicative language skills and exhibited persistent, lifelong deficits in language acquisition despite intensive rehabilitation.
    • Genie's failure to acquire language spontaneously confirms that external linguistic modeling and social interaction are essential components of language acquisition.
• Innate Mechanism Theory:
  • Proposed by Noam Chomsky (referenced in transcript as Nome Chomsky), arguing that human language develops through an innate, biologically predetermined biological module termed the Language Acquisition Device (LAD).
  • Universal Grammar: Chomsky posits that all human languages share a universal underlying grammatical architecture, and humans are born neurologically equipped to decipher these universal rules without formal training.
  • Evidence from deaf children:
    • Congenitally deaf children raised by hearing parents who opted for lip-reading rather than sign language instruction have been studied in both the United States and China.
    • Despite receiving zero instruction in formal sign language, these children spontaneously invented and utilized structured gestural signing systems to communicate.
    • The spontaneous sign systems conformed to consistent, rule-governed grammatical conventions that did not mirror the grammatical syntax of their parents' native spoken languages, pointing to an innate, internal grammar generator.
  • Neurological evidence: Very young infants demonstrate distinct neurophysiological responses to their native language and show an innate preference for human speech sounds over non-speech acoustic stimuli, indicating pre-wired neural architecture.
• Reconciling the Theoretical Debate:
  • The two theories provide complementary explanations where the opposing model fails:
    • Social learning theory cannot account for typical developmental errors:
      • Overextensions: Applying a conceptual label or grammatical rule too broadly. Semantic overextension occurs when an infant calls all four-legged animals "doggie". Syntactic overextension (overregularization) occurs when a child applies standard inflectional rules to irregular forms (e.g., producing "runned" instead of "ran" by improperly generalizing the regular past-tense suffix "-ed").
      • Underextensions: Applying a general term too narrowly (e.g., using "doggie" exclusively for the family pet and refusing to apply it to other dogs, or using "duck" only for a specific toy duck but not living ducks).
      • Because children do not hear adults model errors such as "runned" and are not reinforced for producing them, these novel errors support Chomsky's innate mechanism theory of internal rule generation.
    • Conversely, innate mechanism theory fails to account for the devastating linguistic outcomes of severe social deprivation (such as Genie), which demonstrates the necessity of environmental input and social modeling.

Non-Human Animal Communication vs. True Language

• Complex Communication in the Wild:
  • The Honeybee Waggle Dance:
    • A social communication system used by foraging honeybees to signal the precise location of food sources to other members of the hive.
    • Consists of two distinct alternating phases: the waggle phase and the return phase.
    • Waggle Phase: The bee moves forward in a straight line while vibrating its abdomen. The vertical orientation of the waggle run communicates the direction of the food relative to the sun (a straight vertical path indicates food located directly toward the sun; a path angled away from the vertical indicates the precise angle away from the line of the sun). The duration/distance of the waggle phase communicates the physical distance of the food source from the hive.
    • Return Phase: The bee loops back to the start point, alternating between left and right turns to form a figure-eight trajectory.
    • The waggle dance can involve up to $100$ repetitions, yet remains functionally restricted to a single context (food navigation) with no capacity for open-ended or arbitrary communication.
  • Bird Songs: Complex avian vocalizations used strictly for mate attraction, territorial defense, and competition, lacking productive structural flexibility.
• Primate Language Studies:
  • Washoe (Washu):
    • A chimpanzee taught American Sign Language (ASL) through instrumental conditioning techniques.
    • Evaluated by independent observers, including congenitally deaf individuals.
    • Successfully learned signs for simple requests and combined multiple signs to formulate more complex requests.
    • Criticized by linguists because her signing lacked consistent, rule-governed syntax or regular grammar, falling short of true language criteria.
  • Sarah (Sara):
    • A chimpanzee trained in a laboratory environment to use arbitrarily shaped, colored plastic tokens as communicative symbols on a magnetic board.
    • Acquired a substantial vocabulary and answered simple questions posed by researchers.
    • Failed to demonstrate productivity: she could not spontaneously construct novel combinations of symbols to express unprompted or abstract ideas.
  • Kanzi (Zi):
    • A bonobo/chimpanzee trained to communicate using geometric visual symbols called lexigrams arranged on an electronic keyboard.
    • Acquired lexigram usage through naturalistic environmental immersion and observational learning, rather than explicit operant reinforcement.
    • Demonstrated accurate lexigram usage without requiring external rewards, successfully communicating demands, executing commands, and comprehending novel auditory requests.
    • Despite these achievements, Kanzi exhibited persistent grammatical limitations, demonstrating no understanding of complex syntactic categories (such as nouns, verbs, or plurals) and exhibiting an extremely constrained capacity to combine symbols into novel, creative formulations.
• Conclusion on Animal versus Human Communication:
  • Across empirical investigations involving bees, birds, and non-human primates, non-human communication systems lack the combination of regularity, arbitrariness, and limitless productivity that defines human language.
  • True language functions not merely as an instrument for signaling immediate physiological states, but as a flexible cognitive framework central to human thought, learning, teaching, and cultural transmission.