Multi-Source Translation Methods Lane Schwartz lane@cs.umn.edu - - PowerPoint PPT Presentation

multi source translation methods
SMART_READER_LITE
LIVE PREVIEW

Multi-Source Translation Methods Lane Schwartz lane@cs.umn.edu - - PowerPoint PPT Presentation

Related Work Oracle Experiment Revisiting Och and Ney (2001) Multi-Source Translation Methods Lane Schwartz lane@cs.umn.edu University of Minnesota 23 Oct 2008 Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods Related Work


slide-1
SLIDE 1

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Multi-Source Translation Methods

Lane Schwartz lane@cs.umn.edu

University of Minnesota

23 Oct 2008

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-2
SLIDE 2

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-3
SLIDE 3

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Motivation

Principle of Translational Promiscuity: If a document is translated into more than 1 language, it will likely be translated into many more languages.

◮ Translate into first n target languages by hand ◮ Translate into remaining target languages using MT

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-4
SLIDE 4

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Motivation

Principle of Translational Promiscuity: If a document is translated into more than 1 language, it will likely be translated into many more languages.

◮ Translate into first n target languages by hand ◮ Translate into remaining target languages using MT

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-5
SLIDE 5

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Motivation

Principle of Translational Promiscuity: If a document is translated into more than 1 language, it will likely be translated into many more languages.

◮ Translate into first n target languages by hand ◮ Translate into remaining target languages using MT

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-6
SLIDE 6

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work

Can using multiple sources of information improve translation?

◮ Lattice inputs ◮ Consensus decoding ◮ Hypothesis ranking

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-7
SLIDE 7

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work

Can using multiple sources of information improve translation?

◮ Lattice inputs ◮ Consensus decoding ◮ Hypothesis ranking

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-8
SLIDE 8

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work

Can using multiple sources of information improve translation?

◮ Lattice inputs ◮ Consensus decoding ◮ Hypothesis ranking

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-9
SLIDE 9

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work

Can using multiple sources of information improve translation?

◮ Lattice inputs ◮ Consensus decoding ◮ Hypothesis ranking

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-10
SLIDE 10

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work

Can using multiple sources of information improve translation?

◮ Lattice inputs ◮ Consensus decoding ◮ Hypothesis ranking

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-11
SLIDE 11

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Lattice Input

◮ Begin with alternate representations of a source sentence

Chinese word segmentations Arabic morphological analyses

◮ Align alternate representations into a word lattice ◮ Use standard decoding algorithms, modified to accept lattice

input (Dyer et al., 2008)

◮ Can be extended to accept multilingual inputs

(ongoing work by Josh Schroeder)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-12
SLIDE 12

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Lattice Input

◮ Begin with alternate representations of a source sentence

Chinese word segmentations Arabic morphological analyses

◮ Align alternate representations into a word lattice ◮ Use standard decoding algorithms, modified to accept lattice

input (Dyer et al., 2008)

◮ Can be extended to accept multilingual inputs

(ongoing work by Josh Schroeder)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-13
SLIDE 13

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Lattice Input

◮ Begin with alternate representations of a source sentence

Chinese word segmentations Arabic morphological analyses

◮ Align alternate representations into a word lattice ◮ Use standard decoding algorithms, modified to accept lattice

input (Dyer et al., 2008)

◮ Can be extended to accept multilingual inputs

(ongoing work by Josh Schroeder)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-14
SLIDE 14

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Lattice Input

◮ Begin with alternate representations of a source sentence

Chinese word segmentations Arabic morphological analyses

◮ Align alternate representations into a word lattice ◮ Use standard decoding algorithms, modified to accept lattice

input (Dyer et al., 2008)

◮ Can be extended to accept multilingual inputs

(ongoing work by Josh Schroeder)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-15
SLIDE 15

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Lattice Input

◮ Begin with alternate representations of a source sentence

Chinese word segmentations Arabic morphological analyses

◮ Align alternate representations into a word lattice ◮ Use standard decoding algorithms, modified to accept lattice

input (Dyer et al., 2008)

◮ Can be extended to accept multilingual inputs

(ongoing work by Josh Schroeder)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-16
SLIDE 16

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-17
SLIDE 17

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-18
SLIDE 18

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-19
SLIDE 19

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-20
SLIDE 20

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-21
SLIDE 21

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-22
SLIDE 22

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-23
SLIDE 23

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-24
SLIDE 24

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Consensus Decoding

◮ Given a set of translations, find a consensus translation ◮ Bilingual consensus decoding

(Frederking and Nirenburg, 1994; Bangalore et al., 2001; Jayaraman and Lavie, 2005; Rosti et al., 2007)

◮ Translate source text using n different systems ◮ Align the n output hypotheses into a weighted word lattice ◮ Intersect word lattice with n-gram language model

◮ Multilingual consensus decoding

◮ Matusov et al. (2006) ◮ Japanese and Chinese into English ◮ 4.8 BLEU improvement Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-25
SLIDE 25

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-26
SLIDE 26

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-27
SLIDE 27

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-28
SLIDE 28

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-29
SLIDE 29

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-30
SLIDE 30

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-31
SLIDE 31

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Related Work — Hypothesis Ranking

◮ Given a set of translations, find the best translation in the set ◮ Bilingual language model ranking (Kaki et al., 1999;

Callison-Burch and Flourney, 2001)

◮ Multilingual translation model ranking (Och and Ney, 2001)

◮ Max

ˆ e = arg maxe{p(e) · maxn p(fn|e)} Positive results reported combining up to 3 languages

◮ Prod

ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)}

Positive results reported combining up to 6 languages

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-32
SLIDE 32

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Experiment — Hypothesis Ranking using an Oracle

◮ What are the maximum gains possible

from hypothesis ranking?

◮ Oracle experiment —

choose hypothesis based on WER distance to the reference.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-33
SLIDE 33

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Experiment — Hypothesis Ranking using an Oracle

◮ What are the maximum gains possible

from hypothesis ranking?

◮ Oracle experiment —

choose hypothesis based on WER distance to the reference.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-34
SLIDE 34

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Phrase-based bilingual systems

languages BLEU TER METEOR da-en 28.4 57.5 52.9 de-en 27.3 58.9 52.4 el-en 29.3 56.4 53.6 es-en 32.5 52.8 56.3 fi-en 24.6 62.1 50.4 fr-en 31.9 53.1 55.8 it-en 29.2 57.1 53.7 nl-en 25.7 62.7 50.4 pt-en 31.8 53.7 56.0 sv-en 32.7 52.3 56.6 Results of ten bilingual phrase based decoders into English. All systems were trained on Europarl v3. Test set is Europarl test05. Best results are bold.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-35
SLIDE 35

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Oracle BLEU scores

da de el es fi fr it nl pt sv da — 3.2 3.7 2.4 1.9 2.6 4.0 2.4 2.4 1.7 de — 2.7 2.0 1.9 2.0 3.3 2.7 2.1 1.6 el — 2.1 1.8 2.3 3.7 2.6 2.5 2.5 es — 1.2 3.1 2.4 1.7 3.1 3.7 fi — 1.0 1.9 2.7 1.1 0.6 fr — 2.4 1.6 3.5 3.7 it — 2.4 2.5 2.7 nl — 1.8 1.3 pt — 3.5 sv — Absolute change in BLEU after combining two languages using

  • racle compared with the best BLEU of either language

individually.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-36
SLIDE 36

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Oracle BLEU scores

◮ Oracle improvements ranged from 0.6 to 4.0 BLEU for two

languages

◮ Much greater gains are seen when combining more languages

languages BLEU TER METEOR

  • racle-all

40.8 40.5 62.5 Combining ten systems results in 8.0 BLEU improvement over best bilingual system.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-37
SLIDE 37

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Oracle BLEU scores

◮ Oracle improvements ranged from 0.6 to 4.0 BLEU for two

languages

◮ Much greater gains are seen when combining more languages

languages BLEU TER METEOR

  • racle-all

40.8 40.5 62.5 Combining ten systems results in 8.0 BLEU improvement over best bilingual system.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-38
SLIDE 38

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Oracle All Systems

system % selected da-en 14.1 de-en 9.6 el-en 10.3 es-en 14.0 fi-en 4.0 fr-en 12.9 it-en 7.2 nl-en 5.5 pt-en 9.8 sv-en 12.9 Percentage of time that sentences from each system were selected in an All-English oracle WER experiment. Score for overall oracle

  • utput was 43.8 WER and 40.8 BLEU.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-39
SLIDE 39

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Max in Och and Ney (2001)

Max ˆ e = arg maxe{p(e) · maxn p(fn|e)}

◮ Positive results reported combining up to 3 languages ◮ All reported combinations using Max had positive results ◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Conducted new experiment using larger Europarl corpus.

◮ Experiment using Europarl (10 source languages) ◮ Include longer sentences (average 29 words)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-40
SLIDE 40

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Max in Och and Ney (2001)

Max ˆ e = arg maxe{p(e) · maxn p(fn|e)}

◮ Positive results reported combining up to 3 languages ◮ All reported combinations using Max had positive results ◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Conducted new experiment using larger Europarl corpus.

◮ Experiment using Europarl (10 source languages) ◮ Include longer sentences (average 29 words)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-41
SLIDE 41

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Max in Och and Ney (2001)

Max ˆ e = arg maxe{p(e) · maxn p(fn|e)}

◮ Positive results reported combining up to 3 languages ◮ All reported combinations using Max had positive results ◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Conducted new experiment using larger Europarl corpus.

◮ Experiment using Europarl (10 source languages) ◮ Include longer sentences (average 29 words)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-42
SLIDE 42

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Max in Och and Ney (2001)

Max ˆ e = arg maxe{p(e) · maxn p(fn|e)}

◮ Positive results reported combining up to 3 languages ◮ All reported combinations using Max had positive results ◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Conducted new experiment using larger Europarl corpus.

◮ Experiment using Europarl (10 source languages) ◮ Include longer sentences (average 29 words)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-43
SLIDE 43

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Max in Och and Ney (2001)

Max ˆ e = arg maxe{p(e) · maxn p(fn|e)}

◮ Positive results reported combining up to 3 languages ◮ All reported combinations using Max had positive results ◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Conducted new experiment using larger Europarl corpus.

◮ Experiment using Europarl (10 source languages) ◮ Include longer sentences (average 29 words)

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-44
SLIDE 44

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Experiment — Max

da de el es fi fr it nl pt sv da — 0.4 0.1

  • 0.8
  • 1.3
  • 1.3

0.3

  • 1.4
  • 0.7
  • 1.6

de —

  • 0.2
  • 0.6
  • 0.8
  • 2.0
  • 0.1
  • 0.8
  • 0.8
  • 1.1

el —

  • 0.2
  • 1.8
  • 1.0

0.6

  • 1.9
  • 0.3
  • 0.5

es —

  • 1.5

0.5

  • 0.9
  • 2.6

0.1 0.3 fi —

  • 2.9
  • 1.3
  • 0.3
  • 1.9
  • 2.3

fr —

  • 1.6
  • 3.7

0.2 0.2 it —

  • 1.5
  • 1.0
  • 1.0

nl —

  • 2.4
  • 2.9

pt —

  • 0.1

sv — Absolute change in BLEU after combining two languages using Max ranking method compared with the best BLEU of either language individually. Only 20% of Max pairwise combinations led to an improvement in BLEU.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-45
SLIDE 45

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Prod in Och and Ney (2001)

Prod ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)} ◮ Positive results reported combining up to 6 languages ◮ All but 2 reported combinations using Prod had positive

results

◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Attempted new experiment using larger Europarl corpus.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-46
SLIDE 46

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Revisiting Prod in Och and Ney (2001)

Prod ˆ e = arg maxe{p(e) · N

n=1 p(fn|e)} ◮ Positive results reported combining up to 6 languages ◮ All but 2 reported combinations using Prod had positive

results

◮ No results reported for German-English or Finnish-English ◮ Test sentences were short (10-14 words)

Attempted new experiment using larger Europarl corpus.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-47
SLIDE 47

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Constraint Decoding

Prod requires each system to calculate a translation model probability for the output hypotheses of every system.

◮ n systems each produce one target hypothesis ◮ ˆ

e = arg maxe{p(e) · N

n=1 p(fn|e)} ◮ Each system must calculate p(fn|e) for all n target hypotheses.

da-en de-en es-en fr-en % reachable 10.5 9.8 11.5 10.6 Percentage of sentences reachable by the Swedish-English system when constrained by the output of the listed systems.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-48
SLIDE 48

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Constraint Decoding

Prod requires each system to calculate a translation model probability for the output hypotheses of every system.

◮ n systems each produce one target hypothesis ◮ ˆ

e = arg maxe{p(e) · N

n=1 p(fn|e)} ◮ Each system must calculate p(fn|e) for all n target hypotheses.

da-en de-en es-en fr-en % reachable 10.5 9.8 11.5 10.6 Percentage of sentences reachable by the Swedish-English system when constrained by the output of the listed systems.

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-49
SLIDE 49

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-50
SLIDE 50

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-51
SLIDE 51

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-52
SLIDE 52

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-53
SLIDE 53

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-54
SLIDE 54

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-55
SLIDE 55

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Conclusions

◮ Hypothesis ranking has the potential to produce large

improvements in translation quality

◮ Max does not consistently produce positive results

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ New results show only 20% of Max pairwise combinations led

to an improvement in BLEU.

◮ Unable to replicate Prod

◮ Och and Ney (2001) reported consistent positive results for up

to 3 source languages

◮ Vast majority of hypothesis unreachable during constraint

decoding

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-56
SLIDE 56

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Future Work

◮ Approximate translation model probabilities for Prod ◮ Incorporate system weighting ◮ Multilingual consensus decoding ◮ Multilingual lattice inputs ◮ Multi-synchronous decoding algorithms

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-57
SLIDE 57

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Future Work

◮ Approximate translation model probabilities for Prod ◮ Incorporate system weighting ◮ Multilingual consensus decoding ◮ Multilingual lattice inputs ◮ Multi-synchronous decoding algorithms

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-58
SLIDE 58

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Future Work

◮ Approximate translation model probabilities for Prod ◮ Incorporate system weighting ◮ Multilingual consensus decoding ◮ Multilingual lattice inputs ◮ Multi-synchronous decoding algorithms

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-59
SLIDE 59

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Future Work

◮ Approximate translation model probabilities for Prod ◮ Incorporate system weighting ◮ Multilingual consensus decoding ◮ Multilingual lattice inputs ◮ Multi-synchronous decoding algorithms

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-60
SLIDE 60

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Future Work

◮ Approximate translation model probabilities for Prod ◮ Incorporate system weighting ◮ Multilingual consensus decoding ◮ Multilingual lattice inputs ◮ Multi-synchronous decoding algorithms

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods

slide-61
SLIDE 61

Related Work Oracle Experiment Revisiting Och and Ney (2001)

Thank you!

Thank you! Mahalo!

Lane Schwartz lane@cs.umn.edu Multi-Source Translation Methods