- Human language design features
  - Arbitrariness as a key feature
    - Definition: No logical connection between sound and meaning
      - Example: Book and pen names lack explainable logic
    - Cross-linguistic evidence supports arbitrariness
      - Different sounds for the same object in various languages
        - Classroom (English), 教室 (Chinese), 教室 (Japanese)
        - Teacher (English), 老师 (Chinese), sensei (Japanese)
    - Levels of arbitrariness
      - Morpheme level
        - Arbitrary relationship between sound and meaning
          - Words for the same concept differ across languages
          - Onomatopoeic words partially contradict arbitrariness
            - Examples: hualala vs. crash, honglong vs. rumble, shasha vs. rustle
          - Compound words exhibit reduced arbitrariness
            - Example: Photocopy combines meanings of photo and copy
      - Syntactic level
        - Language is less arbitrary at this level
          - Sentence structure follows rules
          - Clause order reflects real-world sequence
            - Example: She came in and sat down vs. reversed order
- Arbitrariness vs. conventionality
  - Convention defines linguistic signs and meanings
    - Idioms illustrate conventionality
      - Example: "Like peas and carrots" means being together
    - Differences between arbitrariness and conventionality
      - Arbitrariness fosters creativity
      - Conventionality makes language learning laborious
        - Learners focus more on conventionality (e.g., idioms)
- Class summary
  - Definition of arbitrariness
  - Levels of arbitrariness
    - Morpheme level: Arbitrary
    - Syntactic level: Less arbitrary
  - Arbitrariness and conventionality
    - Conventionality impacts language learning more
- Assignment
  - Collect alphanumeric English words and compare with equivalents in Chinese or another language
  - Write a paper on language arbitrariness