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LING 388 Language and Computers

LING 388 Language and Computers. Lecture 24 12/4 /03 Sandiway FONG. Administrivia. Next Tuesday Special lecture Don’t miss it Final will be handed out and discussed in class. Noun-Noun Compounding. Examples: From Lecture 21 ( Stemming ): operating system (OS)

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LING 388 Language and Computers

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  1. LING 388Language and Computers Lecture 24 12/4/03 Sandiway FONG

  2. Administrivia • Next Tuesday • Special lecture • Don’t miss it • Final will be handed out and discussed in class

  3. Noun-Noun Compounding • Examples: • From Lecture 21 (Stemming): • operating system (OS) • negative polarity item (NPI) • Sheer volume of compounds poses a challenge for natural language processing • Parsing: the recovery of meaning • Translation: mapping compounds into target languages • Often abbreviated… • OS, NPI

  4. Noun-Noun Compounding: Semantics • Productive • Examples: • tea leaf • teabag • teabreak • tea garden • tea service • teapot

  5. Noun-Noun Compounding: Semantics • Multiple semantic relationships between elements of the compound possible • Example: (Keene & Costello, 1997) • pencil bed • “a narrow bed” • “a container for pencils” • “a bed shaped like a pencil” • Disambiguating context: • The pencil bed is in the bedroom upstairs • The pencil bed is in the middle of the exam hall • He moved the pencil bed last week

  6. Noun-Noun Compounding: Semantics • Meaning sometimes unpredictable or hard to guess at • Example (made-up): • cousin chair • ???

  7. Noun-Noun Compounding: Idioms • Non-compositional semantics • In earlier lectures, we have seen examples of VP idioms that must be handled specially: • kick the bucket • vp(vp(v(die))) --> [kick,the,bucket]. • Examples: • bootleg • marshmallow

  8. Noun-Noun Compounding: Semantics • Novel compounds sometimes force the introduction of other compounds/words… • Examples: • mountain bike • (invented in the 1970s) • road bike • hybrid

  9. Noun-Noun Compounding • Choice of words sometimes arbitrary? • Example: • soccer mom • soccer mother • Driven by ambiguity reduction? • “mother of soccer” • “*mom of soccer” vs. caregiver

  10. Noun-Noun Compounding • Compositionality • Example: • school girl • “girl who goes to school” • *girl school • “school for girls” • [DP [NP girl] [D ‘s] [NP school]]]

  11. Noun-Noun Compounding • Language-particular • Examples: • house museum (Russian) • bookstore (English) • book-adj store (Russian) • van driver (English) • genitive construction for compounds headed by deverbal nouns? (Russian)

  12. Noun-Noun Compounding • V-N Compounds • Examples: • pickpocket (V-N) • scarecrow (V-N) • scofflaw (V-N) • Not right-headed • Not productive

  13. Noun-Noun Compounding: Conceptual Categories • (Costello & Keene, 1996) More compounds headed by artifacts • Compound formation affected by conceptual categories: • artifacts more polysemous • Example: • elephant gun • “gun used for shooting elephants” • “gun used by elephants” • cherry tree • sub-type relationship only

  14. Noun-Noun Compounding: Syntax • How are compounds formed? • E.g. Relative clause deletion • Example: • girl who goes to school • (girl)(lx.x goes to school) => • school girl • (girl)(lx.x goes to school) • Evidence against this? • Compounding is acquired before relative clause formation (Hoeksema, 1985)

  15. Noun-Noun Compounding: Syntax • Morphological Island Constraint (Botha, 1980) • Compound-internal changes in morphology not possible • Examples: • bus stop • *buses stop • operating system • *operation system • algorithms course • But: • frozen foods section • cf. frozen food section

  16. Noun-Noun Compounding: Headedness • In English, the head of compound is always to the right • Structural ambiguity • (putting aside word sense considerations) • Example: • computer furniture design • [computer furniture] design • The design of computer furniture • computer [furniture design] • Furniture design by computer

  17. Noun-Noun Compounding • Structural ambiguity • Compounds can be long: • Judiciary plea bargain settlement account audit (Gazdar, 1985) • How many ways ambiguous in general? • (N-1)! • (N-1)x(N-2)x(N-3)x..x2x1(factorial) • Combinatorially Explosive: • Problem for parsing

  18. Noun-Noun Compounding • Example: • 1 2 3 4 • 12 3 4 • [12 3] 4 • 12 [3 4] • 1 23 4 • [1 23] 4 • 1 [23 4] • 1 2 34 • [1 2] 34 • 1 [2 34]

  19. Noun-Noun Compounding • Structural ambiguity not present in all languages • Example (Turkish indefinites): • signaled morphologically • [N [N … [N N-POSS] …]] (right-branching) • Turk Language Organization-POSS • [ … [[N N-POSS] N-POSS] … ] (left-branching) • Language Organization- POSS Dictionary-POSS • Both left and right branching possible: • [[Turk [Language Organization-POSS]] Dictionary-POSS]

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