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Linglib.Theories.Syntax.CCG.Intonation

CCG Intonation and Information Structure #

@cite{steedman-2000}'s theory of how prosodic structure aligns with CCG derivations.

Insight #

CCG's "spurious ambiguity" is not spurious: different derivations correspond to different Information Structures, disambiguated by intonation in speech.

The sentence "Anna married Manny" has multiple CCG derivations:

  1. [Anna] [married Manny] — traditional subject-predicate
  2. [Anna married] [Manny] — via composition: theme "Anna married _", rheme "Manny"

Intonation selects among these:

Prosodic Marking #

The INFORMATION feature on CCG categories.

Categories are marked as:

  • θ (theta): Part of the theme
  • ρ (rho): Part of the rheme
  • unmarked: Unspecified (can unify with either)
  • φ (phi): Phrasal (after boundary tone applies)
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      A CCG category with prosodic annotation.

      The INFORMATION feature projects through the category:

      • (Sθ\NPθ)/NPθ: All arguments and result share the same info value
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          def CCG.Intonation.instDecidableEqProsodicCat.decEq (x✝ x✝¹ : ProsodicCat) :
          Decidable (x✝ = x✝¹)
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            A prosodic lexical entry: word + pitch accent → prosodic category.

            The pitch accent determines the INFORMATION feature:

            • H* → ρ (rheme)
            • L+H* → θ (theme)
            • null → unmarked
            • Other accents → ρ (default to rheme for non-theme accents)
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                Get the prosodic category from a lexical entry

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                  An intonational tune: pitch accent + terminal contour.

                  The two main tunes in English (@cite{steedman-2000}):

                  • L+H* L H%: Theme tune (fall-rise)
                  • H* L L%: Rheme tune (fall)
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                    def CCG.Intonation.instReprTune.repr :
                    TuneStd.Format
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                      def CCG.Intonation.instDecidableEqTune.decEq (x✝ x✝¹ : Tune) :
                      Decidable (x✝ = x✝¹)
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                        The canonical theme tune: L+H* with continuation rise (L H%)

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                          The canonical rheme tune: H* with declarative fall (L L%)

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                            Prosodic forward application: X/Y + Y → X Only succeeds if INFORMATION features unify.

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                              Prosodic backward application: Y + X\Y → X Only succeeds if INFORMATION features unify.

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                                Prosodic forward composition: X/Y + Y/Z → X/Z INFORMATION features must unify and project to result.

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                                  Apply a terminal contour to a prosodic category. Converts θ/ρ marking to φ (phrasal).

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                                    A prosodic derivation step. Extends CCG derivations with prosodic information.

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                                        Get the prosodic category of a derivation

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                                          A prosodic phrase: a derivation with a terminal contour applied.

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                                              Extract Information Structure from a sequence of prosodic phrases.

                                              The phrase with theme tune (L+H* L H%) becomes the theme. The phrase with rheme tune (H* L L%) becomes the rheme.

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                                                Prosodic CCG derivations have Information Structure. Wraps extractInfoStructure (Option-typed because not every list of prosodic phrases yields a coherent Theme/Rheme partition) with a default-everything-rheme fallback.

                                                (The previous instance : HasInfoStructure (List ProsodicPhrase) ProsodicDeriv typeclass shape was deleted in the 0.230.489 cleanup since no caller dispatched on the typeclass — see Features/InformationStructure.lean for the rationale. Direct calls suffice.)

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                                                    Check if a prosodic derivation is well-formed (simplified)

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