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CzEng 0.9 (Czech-English Parallel Corpus, version 0.9)

Ondřej Bojar, Zdeněk Žabokrtský
in cooperation with Miroslav Janíček, Václav Klimeš, Jana Kravalová,
David Mareček, Václav Novák, Martin Popel and Jan Ptáček


CzEng 0.9 is the third release of a sentence-parallel Czech-English corpus compiled at the Institute of Formal and Applied Linguistics (ÚFAL) freely available for non-commercial and research purposes.

CzEng 0.9 contains 8.0 million parallel sentences (93 million English and 82 million Czech tokens) from seven different types of sources automatically annotated at surface and deep (a- and t-) layers of syntactic representation. The number of sentences and nodes of a given layer and language per data source is given in the following table:

English Czech
Source Sentences a-layer t-layer a-layer t-layer
Movie Subtitles 3,549,367 26,550,305 16,615,991 22,175,284 16,675,187
EU Legislation 1,589,036 31,725,089 19,458,544 28,484,512 19,310,396
Technical Documentation 1,212,494 9,099,748 6,339,129 8,460,491 6,512,247
Fiction 1,036,952 17,045,233 10,861,341 15,031,926 11,102,760
Parallel Web Pages 464,522 4,946,552 3,666,149 4,750,757 3,667,297
News 140,191 3,196,303 2,019,758 2,945,777 2,220,789
Project Navajo 37,239 612,826 385,292 539,659 405,484
Total 8,029,801 93,176,056 59,346,204 82,388,406 59,894,160

All further details about CzEng 0.9 are in the paper cited below.

Citing CzEng 0.9

If you make use of CzEng data, please make sure to cite CzEng properly. To improve the reproducibility of your results, please indicate which sections have you used for training and/or evaluation.


To download CzEng 0.9, you have to register by filling in the following form. Within a week we will send you a unique username to access the files.


I certify that I will use CzEng 0.9 only for research and non-commercial purposes.


After the registration, you received a unique username. The unique username and a shared password "czeng" will be requested at the following links.

To simplify the download, the 100 sections of CzEng are grouped to packs of 10 sections each. CzEng 0.9 is shuffled so you may wish to use just one of the packs for your experiments as a random sample.

File Format Avg. Download Size Training Sections DevTest Sections EvalTest Sections
TMT, rich XML 2.0 GB each 0* 1* 2* 3* 4* 5* 6* 7* 8* 9*
Export Format, rich factored plaintext 310 MB each 0* 1* 2* 3* 4* 5* 6* 7* 8* 9*
Plaintext, untokenized 45 MB each 0* 1* 2* 3* 4* 5* 6* 7* 8* 9*

Tip for Linux wget tool: Use the flags --user=YOUR-USERNAME --password=czeng to pass the authorization check. Use the flag --continue to continue an interrupted transfer.

Remark for WMT'10 participants: There will be no intersection between CzEng 0.9 EvalTest data and WMT'10 evaluation data. However, WMT10 participants are kindly asked not to use the CzEng 0.9 EvalTest sections (pack 9) for any training purposes, so that there remains some held-out data for evaluating future experiments, such as combining outputs of different MT systems. In any case, please indicate clearly how much data / which sections from CzEng 0.9 you have eventually used.


CzEng 0.9 release was funded by the grants FP7-ICT-2007-3-231720 (EuroMatrix Plus), MSM 0021620838 (Výzkumný záměr informační sekce MFF UK 2005-2010), 1ET101120503 (Integrace jazykových zdrojů za účelem extrakce informací z přirozených text, 2005-2009, Hlaváčová) and LC536 (Integrované centrum počítačového zpracování přirozeného jazyka, 2005-2009, Hajič).
Institute of Formal and Applied Linguistics (ÚFAL)
Ondřej Bojar, bojar <at> ufal.mff.cuni.cz
$Id: index.html 71 2008-10-02 09:22:19Z bojar $