Word Aligners for Machine Translation

Here is a not-complete list of word aligners used for Machine Translation:

1) Unsupervised Aligners
- GIZA++
- fast_align (with cdec)
- pialign
- BerkeleyAligner

2) Supervised Aligners
- BerkeleyAligner
- NILE

(to be updated ...)

pialign - Phrasal ITG Aligner

Link: http://phontron.com/pialign/

Intro: pialign is a package that allows you to create a phrase table and word alignments from an unaligned parallel corpus. It is unlike other unsupervised word alignment tools in that it is able to create a phrase table using a fully statistical model, no heuristics. As a result, it is able to build phrase tables for phrase-based machine translation that achieve competitive results but are only a fraction of the size of those created with heuristic methods.

*** Note: pialign can extract very compact phrase table directly from unaligned parallel data. This is may be very helpful for SMT system in mobile environment.

Nile - Syntax-based Word Alignment Tool

Link: https://code.google.com/p/nile/
Intro: Nile is a supervised, discriminative word alignment package that can make use of arbitrary and overlapping features

Word Alignment Visualization Tool

Link: http://nlg.isi.edu/demos/picaro/

hunalign – sentence aligner

http://mokk.bme.hu/resources/hunalign/

Intro

hunalign aligns bilingual text on the sentence level. Its input is tokenized and sentence-segmented text in two languages. In the simplest case, its output is a sequence of bilingual sentence pairs (bisentences).

In the presence of a dictionary, hunalign uses it, combining this information with Gale-Church sentence-length information. In the absence of a dictionary, it first falls back to sentence-length information, and then builds an automatic dictionary based on this alignment. Then it realigns the text in a second pass, using the automatic dictionary.

Like most sentence aligners, hunalign does not deal with changes of sentence order: it is unable to come up with crossing alignments, i.e., segments A and B in one language corresponding to segments B’ A’ in the other language.

There is nothing Hungarian-specific in hunalign, the name simply reflects the fact that it is part of the hun* NLP toolchain.

hunalign was written in portable C++. It can be built under basically any kind of operating system.

YouAlign - Online document alignment solution

http://www.youalign.com/

"Welcome to YouAlign, your online document alignment solution. No software to purchase, no software to install. With YouAlign you can quickly and easily create bitexts from your archived documents. A YouAlign bitext contains a document and its translation aligned at the sentence level. YouAlign generates TMX files that can be loaded into your translation memory. YouAlign can also generate HTML files that you can publish on the Internet, or use with a full-text search engine to search for terminology and phraseology in context.

YouAlign is powered by the AlignFactory engine, which supports all kinds of formats, including Microsoft Word, Excel and PowerPoint, PDF, HTML, XML, Corel WordPerfect, RTF, Lotus WordPro and plain text."

Alignment Set Toolkit

http://gps-tsc.upc.es/veu/personal/lambert/software/AlignmentSet.html

BerkeleyAligner

http://code.google.com/p/berkeleyaligner/