--- title: "A Program for Aligning Sentences in Bilingual — Gale 1993" description: "Gale and Church tackle sentence alignment: deciding which sentences in a text correspond to which sentences in its translation." authors: ["William A. Gale", "Kenneth W. Church"] year: 1993 venue: "Computational Linguistics" source: "https://aclanthology.org/J93-1004/" licence: "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)" licence_url: "https://creativecommons.org/licenses/by-nc-sa/3.0/" summary_licence: "Elamur Cosmic License" canonical: "https://research.elamur.ai/free/en/papers/gale-1993-program-aligning-sentences-bilingual-corpora/" --- [Elamur Research](https://md.research.elamur.ai/free/en/) · [this page in HTML](https://research.elamur.ai/free/en/papers/gale-1993-program-aligning-sentences-bilingual-corpora/) [home](https://md.research.elamur.ai/free/en/) / [papers](https://md.research.elamur.ai/free/en/papers/) / [1993](https://md.research.elamur.ai/free/en/papers/1993/) / A Program for Aligning Sentences in Bilingual Corpora # A Program for Aligning Sentences in Bilingual Corpora **Authors:** William A. Gale, Kenneth W. Church · **Year:** 1993 · **Venue:** Computational Linguistics · **Licence:** [CC BY-NC-SA 3.0 (ACL Anthology, before 2016)](https://creativecommons.org/licenses/by-nc-sa/3.0/) **Links:** [Publisher's page](https://aclanthology.org/J93-1004/) · [PDF](https://aclanthology.org/J93-1004.pdf) · [OpenAlex](https://openalex.org/W1489181569) **Citations:** 945 citations (openalex-snapshot · 2026-10-14) · [339](#cited-by) in our library, of the 140884 papers whose bibliographies we read ## Summary Gale and Church tackle sentence alignment: deciding which sentences in a text correspond to which sentences in its translation. This is a prerequisite for statistical machine translation and bilingual lexicography. Earlier systems were mostly unpublished, slow, or poorly evaluated. The authors present a program, align, that uses no lexical information. It relies only on the observation that sentence lengths, counted in characters, are strongly correlated across translations. Each candidate pairing is scored probabilistically from the normalized length difference and its variance, including 1-1, 1-2, 2-1 and 2-2 matches. Dynamic programming then selects the most likely overall alignment. Paragraphs are aligned first, then sentences within each paragraph. On a trilingual UBS corpus of banking reports in English, French and German, about 4% of alignments were wrong. Keeping only the highest-scoring alignments yields a much cleaner subset. The authors also aligned roughly 90 million words of Canadian Hansards for release through ACL/DCI. The method's speed, simplicity and openness made large parallel corpora practical to use. ## Key points - The evaluation data were 15 UBS economic reports, with 14,680 words, 725 sentences and 188 paragraphs on the English side. Across English-French and English-German, the overall error rate was 4.2% on 1316 alignments, with English-French producing more errors. - Restricting output to the best-scoring 80% of alignments cut the error rate to 0.7%. - Counting length in characters worked better than counting words. Word-based lengths raised the error rate from 4.2% to 6.5%. Paragraph lengths and their translations correlated at 0.991. - The same language-independent parameters were used for both language pairs. Fitting pair-specific values left the total error count unchanged. - The aligned Canadian Hansards (about 90M words) were released via ACL/DCI, and the paper includes C code for the program's core. Later extensions added hard and soft delimiters, and the authors suggest lexical cues as a future fallback. *Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.* Fields: [Linguistics & languages](https://md.research.elamur.ai/free/en/shelves/linguistics/) · [Machine translation](https://md.research.elamur.ai/free/en/shelves/machine-translation/) · [Natural language processing](https://md.research.elamur.ai/free/en/shelves/nlp/) ## Cited by Cited by 339 papers of our library cite it (of the 140884 whose bibliographies we read); 25 of them have a page here, 314 not yet. - [The AMARA Corpus: Building Parallel Language Resources for the Educational Domain](https://md.research.elamur.ai/free/en/papers/abdelali-2014-amara-corpus-building-parallel-language/) - [Adaptive Sentence Boundary Disambiguation](https://md.research.elamur.ai/free/en/papers/aclbulk-1994-palmer-adaptive-sentence-boundary-disambiguation/) - [SmolKalam: Ensemble Quality-Filtered Translation at Scale for High Quality Arabic Post-Training Data](https://md.research.elamur.ai/free/en/papers/alrashed-2025-smolkalam-ensemble-quality-filtered-translation/) - [A Survey of Paraphrasing and Textual Entailment Methods](https://md.research.elamur.ai/free/en/papers/androutsopoulos-2009-survey-paraphrasing-textual-entailment-methods/) - [ParaCrawl: Web-Scale Acquisition of Parallel Corpora](https://md.research.elamur.ai/free/en/papers/banon-2020-paracrawl-web-scale-acquisition-parallel/) - [Extracting Paraphrases from a Parallel Corpus](https://md.research.elamur.ai/free/en/papers/barzilay-2001-extracting-paraphrases-parallel-corpus/) - [Sentence Alignment for Monolingual Comparable Corpora](https://md.research.elamur.ai/free/en/papers/barzilay-2003-sentence-alignment-monolingual-comparable-corpora/) - [Transformation-Based Error-Driven Learning and Natural Language Processing: A Case Study in Part-of-Speech Tagging](https://md.research.elamur.ai/free/en/papers/brill-1995-transformation-based-error-driven-learning/) - [Aligning Sentences in Parallel Corpora](https://md.research.elamur.ai/free/en/papers/brown-1991-aligning-sentences-parallel-corpora/) - [Aligning Sentences in Bilingual Corpora Using Lexical Information](https://md.research.elamur.ai/free/en/papers/chen-1993-aligning-sentences-bilingual-corpora-lexical/) - [Accurate Methods for the Statistics of Surprise and Coincidence](https://md.research.elamur.ai/free/en/papers/dunning-1993-accurate-methods-statistics-surprise-coincidence/) - [An IR Approach for Translating New Words from Nonparallel, Comparable Texts](https://md.research.elamur.ai/free/en/papers/fung-1998-ir-approach-translating-new-words/) - [Text-Translation Alignment](https://md.research.elamur.ai/free/en/papers/kay-1993-text-translation-alignment/) - [Generating Phrasal and Sentential Paraphrases: A Survey of Data-Driven Methods](https://md.research.elamur.ai/free/en/papers/madnani-2010-generating-phrasal-sentential-paraphrases-survey/) - [Improving Machine Translation Performance by Exploiting Non-Parallel Corpora](https://md.research.elamur.ai/free/en/papers/munteanu-2005-improving-machine-translation-performance-exploiting/) - [Automatic Identification of Word Translations from Unrelated English and German Corpora](https://md.research.elamur.ai/free/en/papers/rapp-1999-automatic-identification-word-translations-unrelated/) - [PySBD: Pragmatic Sentence Boundary Disambiguation](https://md.research.elamur.ai/free/en/papers/sadvilkar-2020-pysbd-pragmatic-sentence-boundary-disambiguation/) - [Align and Shine: Building High-quality Sentence-aligned Corpora for Multilingual Text Simplification](https://md.research.elamur.ai/free/en/papers/sanchez-2026-align-shine-building-high-quality/) - [Using cognates to align sentences in bilingual corpora](https://md.research.elamur.ai/free/en/papers/simard-1992-cognates-align-sentences-bilingual-corpora/) - [Translating Collocations for Bilingual Lexicons: A Statistical Approach](https://md.research.elamur.ai/free/en/papers/smadja-1996-translating-collocations-bilingual-lexicons-statistical/) - [Dirt Cheap Web-Scale Parallel Text from the Common Crawl](https://md.research.elamur.ai/free/en/papers/smith-2013-dirt-cheap-web-scale-parallel/) - [The JRC-Acquis: A Multilingual Aligned Parallel Corpus with 20+ Languages](https://md.research.elamur.ai/free/en/papers/steinberger-2006-jrc-acquis-multilingual-aligned-parallel/) - [Vecalign: Improved Sentence Alignment in Linear Time and Space](https://md.research.elamur.ai/free/en/papers/thompson-2019-vecalign-improved-sentence-alignment-linear/) - [Stochastic Inversion Transduction Grammars and Bilingual Parsing of Parallel Corpora](https://md.research.elamur.ai/free/en/papers/wu-1997-stochastic-inversion-transduction-grammars-bilingual/) - [Multi-Source Neural Translation](https://md.research.elamur.ai/free/en/papers/zoph-2016-multi-source-neural-translation/) ## Cite The paper itself, not this page. BibTeX from the library's record of the work. ```bibtex @article{gale1993program, title = {{A Program for Aligning Sentences in Bilingual Corpora}}, author = {Gale, William A. and Church, Kenneth W.}, journal = {Computational Linguistics}, year = {1993}, doi = {10.5555/972450.972455}, url = {https://doi.org/10.5555/972450.972455} } ``` - [next → Accurate Methods for the Statistics of Surprise and Coincidence](https://md.research.elamur.ai/free/en/papers/dunning-1993-accurate-methods-statistics-surprise-coincidence/) - [↑ back to papers of 1993](https://md.research.elamur.ai/free/en/papers/1993/) ## References 11 references, 3 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet. 1. Abramowitz, M., and Stegun, I. (1964). Handbook of Mathematical Functions. US Government Printing Office. 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