Words connect through meaning, shaping how we use language. Semantic relations like synonyms, antonyms, and hyponyms create networks of related concepts. Understanding these links helps us grasp vocabulary structure and word choices.

Thematic roles reveal how words interact in sentences. They show who does what to whom, helping us interpret meaning. Roles like Agent, Patient, and Instrument clarify relationships between verbs and their arguments, deepening our understanding of sentence structure.

Semantic Relations

Types of semantic relations

• Semantic relations connect words or concepts based on meanings shape vocabulary and language structure
• Synonymy involves words with similar or identical meanings (big/large, smart/intelligent, happy/joyful)
• Antonymy encompasses words with opposite meanings
  • Gradable antonyms exist on a spectrum (hot/cold, big/small)
  • Complementary antonyms are mutually exclusive (alive/dead, on/off)
  • Relational antonyms describe reciprocal relationships (teacher/student, parent/child)
• Hyponymy establishes hierarchical relationships between general terms (hypernyms) and specific instances (hyponyms)
  • Hypernym: flower
  • Hyponyms: rose, tulip, daisy
• Meronymy represents part-whole relationships (finger/hand)
• Homonymy occurs when words have same form but different meanings (bank - financial institution/river edge)
• Polysemy involves words with multiple related meanings (head - body part/leader)

Concept of thematic roles

• Thematic roles describe semantic relationships between predicates and arguments show how participants engage in actions or states expressed by verbs
• Roles provide crucial information about who does what to whom in sentences help disambiguate similar structures contribute to overall coherence and interpretation
• Core thematic roles include:
  • Agent initiates or performs an action
  • Patient undergoes or is affected by the action
  • Theme experiences change of state or location
  • Experiencer perceives or experiences a mental state
  • Instrument serves as means for action performance

Assignment of thematic roles

• Identifying thematic roles involves:

  1. Locating the main predicate (typically a verb)
  2. Determining number of associated arguments
  3. Analyzing semantic relationships between arguments and predicate

• Examples of role assignment:

  • "John [Agent] broke the window [Patient] with a rock [Instrument]"
  • "Mary [Experiencer] heard a loud noise [Theme]"
  • "The book [Theme] is on the table [Location]"

• Context may influence role assignment some arguments can have multiple possible roles passive constructions alter surface representation of roles

Interaction of semantics and roles

• Verbs select arguments based on semantic properties hyponymy relationships affect which nouns fill certain roles
• Synonymous verbs often share similar thematic role structures ("give" and "donate" involve Agent, Theme, Recipient)
• Antonymous verbs may reverse thematic roles ("buy" - Agent is buyer vs "sell" - Agent is seller)
• Polysemous words require different thematic role structures for various senses ("run" as physical action vs managing a business)
• Complex sentences involve shared or distinct roles in coordinate structures subordinate clauses introduce additional role relationships
• Semantic classes of nouns exhibit role prototypicality (animate nouns as Agents, inanimate nouns as Instruments)