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Machine Translation Divergences: A Formal Description and Proposed Solution

Machine Translation Divergences: A Formal Description and Proposed Solution. Bonnie J. Dorr University of Maryland Presented by: Soobia Afroz. What is Machine translation Divergence?. Source Language  Machine Translation System ~~cross-linguistic distinctions  Target Language

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Machine Translation Divergences: A Formal Description and Proposed Solution

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  1. Machine Translation Divergences:A Formal Description and ProposedSolution Bonnie J. Dorr University of Maryland Presented by: Soobia Afroz

  2. What is Machine translation Divergence? Source Language  Machine Translation System ~~cross-linguistic distinctions  Target Language 2 distinctions between source language and target language: Translation divergences: The same information is conveyed in the source and target texts, but the structures of the sentences are different. Translation mismatches: The information that is conveyed is different in the source and target languages First type is the focus of this paper.

  3. Formal Definitions Lexical conceptual structure (LCS) An LCS used to map between interlingual reps and surface syntactic reps and conforms to the following structural form: [T(X') X' ([T(W') Wt], [T(Zq) Ztl] "'" [T(Z',,) Ztn] [T(Q',) Q'I] - " [T(Q',,,) Q'm])] Where, X' = the logical head W' = the logical subject Z~... Z~ = the logical arguments Q~ ... Q~m= the logical modifiers T(~)= the logical type (Event, State, Path, Position, etc.) corresponding to the primitive ~ (CAUSE, LET, GO, STAY, BE, etc.)

  4. Example LCS: The LCS representation of “John went happily to school”: [Event GO_Loc ([Thing JOHN], [Path TO_Loc ([Position AT_Loc ([Thing JOHN], [Location SCHOOL])])] [M . . . . . HAPPILY])]

  5. RCLS AND CLCS: Compopsed LCS (CLCS) = An instantiated LCS that is the result of combining two or more RLCSs by means of unification. This is the interlingua, or language-independent, form that serves as the pivot between the source and target languages. Example: Compose the RLCS for “go” with the RLCSs for John ([ThingJOHN]), school ([Location SCHOOL]), and happily ([Manner HAPPILY]), to get the CLCS corresponding to “John went happily to school”:

  6. Syntactic Phrase: A fundamental component of the mapping between the interlingual representation and the surface syntactic representation. Example: “ John went happily to school” = [C-MAX [I-MAX [N-MAX John] [V-MAX [v went] [ADV happily] [P-MAX to [N-MAX school]]]]] Where, The syntactic head is [v went] The external argument is [N-MAX John] The internal argument is [P-MAX a ...] The syntactic adjunct is [ADV happily]

  7. Formalizing the Mapping: Generalized linking routine GLR: Systematically relates syntactic positions from LCS Definition and Syntactic Phrase Definition 4 as follows: 1. X’ =~ X 2. W‘ =~ W 3. Z1’…Z’n =~ Z1… Zn 4. Q‘1…Q'm =~ Q1… Qm

  8. Formalizing the Mapping: Canonical syntactic realization (CST): Systematically relates an LCS type T(phi’) to a syntactic category CAT(phi), where phi’ is a CLCS constituent related to the syntactic constituent phi by the GLR. Example: LCS type ‘Thing’  Syntactic category N, which is ultimately projected up to a maximal level (i.e., N-MAX)

  9. GLR mapping between the CLCS and the syntactic structure Where,X= Logical head Q= Syntactic adjunctW= External ArgZ= Internal Arg

  10. 1. Thematic Divergence

  11. 1. Thematic Divergence

  12. 2. Promotional Divergence

  13. 2. Promotional Divergence

  14. 3. Demotional Divergence

  15. 3. Demotional Divergence

  16. 4. Structural Divergence

  17. 4. Structural Divergence

  18. 5. Conflational Divergence

  19. 5. Conflational Divergence

  20. 6. Categorial divergence: It is characterized by a situation in which CAT(phi) is forced to have a different value than would normally be assigned to T(~phi). E: I am hungry ~ G: Ich habe Hunger 'I have hunger‘ Here, the predicate is adjectival (hungry) in English but nominal (Hunger) in German. 7. Lexical divergence: Lexical divergence arises only in the context of other divergence types. For example, in the following example, a conflational divergence forces the occurrence of a lexical divergence. E: John broke into the room ~ S: Juan forz6 la entrada al cuarto 'John forced (the) entry to the room‘ Here, the event is lexically realized as the main verb break in English but as a different verb forzar (literally force) in Spanish.

  21. Conclusion Proposed system addresses following issues: • Lexical selection: The task of deciding what target-language words accurately reflect the meaning of the corresponding source-language words, so matching the LCS-based interlingua (the CLCS) against the LCS-based entries (the RLCS) in the dictionary in order to select the appropriate word • Syntactic realization: The task of determining how target-language words are mapped to their appropriate syntactic structures, so realizing the positions marked by * (and other parametric markers) into the appropriate syntactic structure.

  22. Conclusion (..cont’d) • Proposed system is used in UNITRAN • Does not use rules specifically tailored to source-target language • Translates one sentence at a time (so mismatch between number of sentences in s-t language not allowed)

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