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Using Named Entity Recognition to improve Machine Translation. Neeraj Agrawal Ankush Singla. Named Entities ( NEs ) Important Part of a Sentence No special treatment in current MT systems Results in dropping or mistranslations Chinese: 27 日 中午 , 他们 已 被 安全 转移 到 普吉岛
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Using Named Entity Recognitionto improveMachine Translation Neeraj Agrawal AnkushSingla
Named Entities (NEs) • Important Part of a Sentence • No special treatment in current MT systems • Results in dropping or mistranslations Chinese: 27日 中午 , 他们 已 被 安全 转移 到 普吉岛 Ref: they were safely moved to phuket island at noon on the 27 . Translation: 27 noon , they have been shifted to safe places to 3pm
Adding NEs to training data • Helps the aligner • Increases the probability of the corresponding translations • Added about 0.7M bilingual NEs to training data after pre-processing
Improvement Ref: they were safely moved to phuket island at noon on the 27 . Translation: at noon on the 27th , and they have been shifted to safe places to phuket . Limitation Ref: bush has also admitted that the training results of iraqisecurity. . . . Translation: interim national security seventy - buhi also admitted that . . .
Adding extra feature • Source and target should have same number of NEs Feature Value = exp ( abs ( Diff. in # of proper nouns in source and target ) ) • Used number of proper nouns in absence of a good NER • The additional feature is given a negative weight by MERT (-0.03)
Chinese: 强生 说 : " 她 已经 沈沦 到底 了 。 “ Reference: " she 's gone off the deep end , " johnson says . Base case : johnson and johnson said : " she has been to the end . " Cur model: johnson said : " she has been to the end . " Chinese: . . . 中国 总理 . . . Reference : chinese premier Base case: chinese prime minister Cur model: chinese premier
Class Based Language Model • NEs given low prob. if they don’t appear in training data: “David is going for a walk” “Ankit is going for a walk” • Replace person and organization names by special tokens
Improvement: Reference: however , powell still firmly holds . . . Base case: but the ball still insisted that the . . . Cur model: however , powell still insisted that the . . . Limitation: Base case: . . .with the support of about 30 people , shook hands , . . . Reference: " the president shook hands with around 30 supporters before . . Cur model: . . . about 30 people supportpresident jiang and deputy president jiangshook hands with . . . .
Conclusion • NEs should be treated separately • Reduced dropping / mistranslation • Helped improve human readability