![Compositionality as set intersection
• [NP Blue books]
– Blue set of everything blue
• Books
– Set of all books
• Blue ∩ Books =[NP Blue books]
• Verbs are more complex they map relationships](https://image.slidesharecdn.com/semantics-200408221459/85/Semantics-8-320.jpg)
Semantics
- 1. Semantics: The Meaning of Language Fromkin et al. Chapter 3 (9th Ed.)
- 2. The Meaning of Language • When you know a language you know: • • When a word is meaningful or meaningless, when a word has two meanings, when two words have the same meaning, and what words refer to (in the real world or imagination) • • When a sentence is meaningful or meaningless, when a sentence has two meanings, when two sentences have the same meaning, and whether a sentence is true or false (the truth conditions of the sentence) • Semantics is the study of the meaning of morphemes, words, phrases, and sentences – Lexical semantics: the meaning of words and the relationships among words – Phrasal or sentential semantics: the meaning of syntactic units larger than one word
- 3. Truth • • Compositional semantics: formulating semantic rules that build the meaning of a sentence based on the meaning of the words and how they combine – Also known as truth-conditional semantics because the speaker’s knowledge of truth conditions is central
- 4. Truth • If you know the meaning of a sentence, you can determine under what conditions it is true or false – You don’t need to know whether or not a sentence is true or false to understand it, so knowing the meaning of a sentence means knowing under what circumstances it would be true or false • Most sentences are true or false depending on the situation – But some sentences are always true (tautologies) – And some are always false (contradictions)
- 5. Entailment and Related Notions • Entailment: one sentence entails another if whenever the first sentence is true the second one must be true also Jack swims beautifully. Jack swims entails but does not entail. Jack swims Jack swims beautifully • When two sentences entail each other, they are synonymous, or paraphrases Jack postponed the meeting Jack put off the meeting • When one sentence entails the negation of another sentence, the two sentences are contradictions Jack is alive Jack is dead
- 6. Ambiguity •Our semantic knowledge also tells us when words or phrases have more than one meaning, or are ambiguous – Syntactic ambiguity arises from multiple syntactic structures corresponding to the same string of words • The boy saw the man with the telescope – Lexical ambiguity arises from multiple meanings corresponding to the same word or phrase • This will make you smart
- 7. Compositional Semantics •Compositional semantics: to account for speakers’ knowledge of truth, entailment, and ambiguity, we must assume that grammar contains semantic rules for how to combine the meanings of words into meaningful phrases and sentences – The principle of compositionality asserts that the meaning of an expression is composed of the meaning of its parts and how the parts are combined structurally
- 8. Compositionality as set intersection • [NP Blue books] – Blue set of everything blue • Books – Set of all books • Blue ∩ Books =[NP Blue books] • Verbs are more complex they map relationships
- 9. Semantic Rules • Semantic Rule I: if the meaning of NP (an individual) is a member of the meaning of the VP (a set of individuals), then S is TRUE, otherwise, it is FALSE Word Meaning Jack refers to the individual Jack swims refers to the set of individuals that swim • If the NP, Jack, is among the set of individuals that swims (the VP) then the sentence is TRUE
- 10. Semantic Rules
- 11. Semantic Rules • If the NP Jack is among the set of people who kissed Laura (the VP), then the sentence is TRUE
- 12. Semantic Rules • The meaning of the sentence Jack kissed Laura is first derived by applying Semantic Rule II, which establishes the meaning of the VP (establishes the set of people who kissed Laura) • Then, Semantic Rule I applies to determine the meaning of the entire sentence (establishes whether or not Jack in particular is in the set of people who kissed Laura
- 13. When Compositionality Goes Awry: Anomaly • An anomalous sentence: Colorless green ideas sleep furiously • This sentence is syntactically fine, but contains semantic violations such as describing ideas as both colorless and green • Other sentences are uninterpretable because they include nonsense words: He took his vorpal sword in hand
- 14. When Compositionality Goes Awry: Metaphor • Metaphors are sentences that seem to be anomalous but are understood in terms of a meaningful concept • To understand a metaphor we must understand the individual words, the literal meaning of the expression, and facts about the world – To understand Time is money you need to know that in our society people are often paid according to the amount of time worked
- 15. When Compositionality Goes Awry: Idioms • Idiomatic phrases are phrases with meanings that cannot be predicted based on the meanings of the individual words – The usual semantic rules for combining meanings do not apply drop the ball (fail) put his foot in his mouth (goof) hit it off (get on with, agree) • All languages have idioms, but idioms are rarely directly translatable kick the bucket = estirar la pata “to stretch the (animal) leg”
- 16. Lexical Semantics: Reference • Referent: the meaning of a word is its referent, which is the thing or things in the real world that it refers to. – Jack, the happy swimmer, my friend, and that guy can all have the same referent in the sentence Jack swims. – But, some NPs do not refer to any particular individual, such as: No baby swims. – While the happy swimmer and Jack may refer to the same individual in some cases, the happy swimmer means something extra, which a tautology: • The happy swimmer is happy. • Jack is happy.
- 17. Lexical Semantics: Sense • Sense: an element of meaning separate from reference and more enduring; the manner in which an expression presents the reference (two expressions may refer to the same individual but not have the same meaning.) – Barack Obama These have the same reference but – The President different senses – Michelle Obama’s husband • The word Harry Potter has sense but no reference (in the real word) • Proper names tend to have reference but no sense – Sometimes two proper names have the same referent (Mark Twain and Samuel Langhorne Clemens); these pairs of nouns are called coreferential
- 18. Lexical Relations: Synonyms • Synonyms: words or expressions that have the same meaning in some or all contexts – apathetic, indiferent sofa, couch • Some assert that there are no two words with exactly the same meanings • After the Norman invasion of England in 1066, many French words of Latin origin entered the language, giving rise to synonymous pairs: – English: heal Latin: recuperate – English: send Latin: transmit
- 19. Lexical Relations: Antonyms • Antonyms are words that are opposite in meaning – Complementary antonyms: • alive/dead, present/absent, awake/asleep • alive = not dead, dead = not alive – Gradable pairs: no absolute scale • big/small, hot/cold, fast/slow, happy/sad (A small elephant is much bigger than a large mouse.) (Fast is faster when applied to an airplane than to a car.) • Some pairs of gradable antonyms contain a marked and an unmarked term, with the unmarked term being the one used in questions of degree: – How high is the mountain? not How low is the mountain?
- 20. Lexical Relations: Antonyms – Relational antonyms: display symmetry in their meaning • give/receive, buy/sell, employer/employee – “Autoantonyms” or “contranyms” are words that are their own antonym • dust = to remove small particles • dust = to scatter small particles -Prefix as a way of forming antonyms: likely/unlikely tolerant/intolerant
- 21. Lexical Relations • Homonyms or Homophones: words that have different meanings but are pronounced the same: bear and bare • – Homographs are words that are spelled the same: bear and bear, dove and dove • – Heteronyms are words that are spelled the same but pronounced differently: Lead, pronounced LEED, means to guide. However, lead, pronounced LED, means a metallic element.
- 22. Lexical Relations • Polysemous words are words with multiple, conceptually or historically related meanings – diamond: the geometric shape; a baseball field • Hyponyms involve the relationship between a general term and specific instances of that term – rose, iris, daisy, and poppy are all a kind of flower, so rose, iris, daisy, and poppy are all hyponyms of the word flower
- 23. Semantic Features • Semantic features are properties that are part of word meanings and reflect our knowledge about what words mean – For example, antonyms share all but one semantic feature • big has the semantic feature “about size” and red has the semantic feature “about color,” so the two cannot be antonyms – The semantic features of the word assassin include that assassins must be human and kill important people
- 24. Evidence for Semantic Features • Speech errors, or “slips of the tongue” provide evidence for semantic features because the accidentally uttered word shares semantic features with the intended word: Intended Utterance Actual Utterance (Error) Bridge of the nose bridge of the neck my when gums bled when my tongues bled he came too late he came too early Mary was young Mary was early • Here nose, neck, gums, and tongues all share the property of being body parts or parts of the head; early, late, and young all have to do with time
- 25. The Difference Between Error and Mistake • Errors are made due to lack of knowledge and reflect the competence of the learner. The person who is making the error doesn’t know that he is doing something wrong. • Mistakes are accidental. The person who made the mistake has knowledge, even though did it inaccurately. It may be carelessness that resulted in a mistake. The person who made the mistake may be able to identify his own mistake. The hesitations, slips of the tongue, random ungrammaticalities, and other performance lapses in native-speaker production also occur in second language speech.
- 26. Semantic Features of Nouns • Some languages have classifiers, or grammatical morphemes that indicate the semantic class of the noun – Swahili has one set of singular and plural markers for nouns that have the semantic feature “human” and another set for those that don’t • In English the type of determiner that accompanies a noun depends on whether it is a count noun (can be enumerated and pluralized) or a mass noun (cannot be enumerated or pluralized) – Count nouns such as dog and potato can be counted and pluralized (I have two dogs) – Mass nouns such as rice and water cannot be pluralized or counted (*I have two rices) and do not take the article a (*I have a rice)
- 27. Semantic Features of Verbs • Verbs also have semantic features attached to them – darken includes the semantic feature “cause”, as does kill and uglify – break can be analyzed as follows: “cause” to “become” broken • The semantic features of verbs can also have syntactic consequences
- 28. Semantic Features of Verbs • Verbs can describe events (eventives) or states (statives), and these verbs affect the possible sentence structures: – Eventive sentences sound good when passivized, put in the progressive, used as imperatives, and with certain adverbs: Eventive: Oysters were eaten by John Eventive: John is eating oysters Statives: ?Oysters were liked by John Stative: ?John is liking oysters Eventive: John deliberately ate oysters Eventive: Eat oysters! Stative: ?John deliberately liked oysters Stative: ?Like oysters!
- 29. Argument Structure • Different kinds of verbs take a different number of NPs as arguments—each verb takes a subject and: • – Intransitive verbs such as sleep take no other arguments • – Transitive verbs such as find take an additional argument (a direct object) • – Ditransitive verbs such as give take two additional arguments (direct and indirect objects) • The verb also determines the semantic properties of all the arguments – Verbs such as find and sleep require human subjects – Verbs such as drink require a liquid direct object
- 30. Thematic Roles • Thematic roles express the relation between the arguments of the verb and the situation the verb describes • – Agent: the ‘doer’ of the action • – Theme: the ‘undergoer’ of the action • – Goal: the endpoint of a change in location or possession • – Source: where the action originates • – Instrument: the means used to accomplish an action • – Experiencer: one receiving sensory input
- 31. Thematic Roles • Thematic roles remain the same in paraphrases because the thematic roles are in their proper place in deep structure
- 32. Other thematic roles (from Luca)
- 33. Pragmatics • Pragmatics is concerned with our understanding of language in context – Linguistic context: the discourse that precedes the phrase or sentence to be interpreted – Situational context: everything nonlinguistic in the environment of the discourse
- 34. Pronouns and Linguistic Context • Pronouns get their meaning from other NPs in the sentence or discourse – Any NP that a pronoun relies on for its meaning is called an antecedent • Reflexive pronouns always depend on an antecedent in the same clause for its meaning John bit himself *John said that the girl bit himself *Himself left • Regular pronouns cannot refer to an antecedent in the same clause John knows him (him cannot refer to John) John knows that he is a genius (he can refer to John or someone else)
- 35. Deixis • Deixis refers to words and expression whose reference depend on the situational context • – Person deixis: I, you, she, that man, those girls • The meaning depends on who is present or being discussed • – Time deixis: now, then, tomorrow, yesterday • The meaning depends on when the utterance was said or what period of time is being discussed • – Place deixis: here, there, yonder mountains • The meaning depends on where the utterance was said or what place was being discussed
- 36. Maxims of Conversation • Maxims of conversation are conversational conventions that govern discourse: – Maxim of Quality: Truth – Maxim of Quantity: Information – Maxim of Relation: Relevance – Maxim of Manner: Clarity • People tend to adhere to these maxims and expect others to do so also – Therefore, if someone suddenly says, “It’s cold in here” to someone standing by an open window, the listener can assume the speaker is violating the maxim of relevance, or she can assume that the utterance is relevant because the speaker would like the window closed
- 37. Implicatures • Implicatures are inferences that may be drawn from an utterance based on context – SUE: Does Mary have a boyfriend? – BILL: She’s been driving to Santa Barbara every weekend. • Bill asserts that Mary drives to Santa Barbara every weekend and implicates that she has a boyfriend living in Santa Barbara
- 38. Speech Acts • The study of speech acts describes how people do things with language • Performative verbs: verbs that accomplish an action when they are uttered – When you say, I dare you have said something and you have dared someone – Some performative verbs: bet, challenge, dare, fine, nominate, promise, resign – A test for performativity: performative verbs usually sound good when you add I hereby to the sentence: • I hereby resign • ?I hereby know you