Uighur and Turkish/GSoC2018 report
This project was an application of Apertium to develop an MT between Uyghur and Turkish, two Turkic languages. The project consisted mainly of building a bilingual bidix, writing transfer and disambiguation rules and enriching the Uyghur morphological analyzer.
Contents
Commits
My commits can be found here. You can also download my work as a zip file.
Corpora and Coverage
Our main corpora consisted of RFA, Tanritor, TRT Uyghurche and Uyghur Wikipedia, but we also worked on some Uyghur blogs, a collection of Uyghur stories and the Uyghur translation of the Bible to be able to cover different domains. Wikipedia and blog coverages were relatively low due to nonstandard forms, Arabic and Farsi texts and alphabets.
| Corpus | Words | Coverage |
|---|---|---|
| News | 3447048 | 94.0% |
| Bible | 1527061 | 94.1% |
| Wikipedia | 1589113 | 88.2% |
| Blogs | 4055981 | 87.0% |
Transfer
There are about 50 transfer rules, mostly needed to cover Uyghur's relatively richer tense inventory. We also needed transfer rules for expression that are -optionally- expressed synthetically in Uyghur but was analytic in Turkish. To give some examples:
bolidighan and bolmaqchi in Uyghur are both equivalents of Turkish olacak.
Uyghur can use the -rAK for comparisons, which is expressed by the preposition daha in Turkish.
Disambiguation
To correctly discern the lemma and the morphology so as to be translated correctly into the target language, Apertium uses Constraint Grammar (CG). Currently Uyghur has about 45 CG rules for disambiguation.
Lexical Selection
To determine in which context which translation of a given lemma would be selected, lexical selection is employed. Currently uig-tur has 35 lexsel rules.
WER results
Here is the WER result before I added the unknown words/wrote some CG rules for the text:
Test file: 'wikiwertr0.txt' Reference file 'wikiwertur.txt' Statistics about input files ------------------------------------------------------- Number of words in reference: 1068 Number of words in test: 1105 Number of unknown words (marked with a star) in test: Percentage of unknown words: 0.00 % Results when removing unknown-word marks (stars) ------------------------------------------------------- Edit distance: 394 Word error rate (WER): 36.89 % Number of position-independent correct words: 731 Position-independent word error rate (PER): 35.02 % Results when unknown-word marks (stars) are not removed ------------------------------------------------------- Edit distance: 394 Word Error Rate (WER): 36.89 % Number of position-independent correct words: 731 Position-independent word error rate (PER): 35.02 % Statistics about the translation of unknown words ------------------------------------------------------- Number of unknown words which were free rides: 0 Percentage of unknown words that were free rides: 0%
And after:
Test file: 'wikiwertrlast.txt' Reference file 'wikiwertur.txt' Statistics about input files ------------------------------------------------------- Number of words in reference: 1068 Number of words in test: 1065 Number of unknown words (marked with a star) in test: Percentage of unknown words: 0.00 % Results when removing unknown-word marks (stars) ------------------------------------------------------- Edit distance: 179 Word error rate (WER): 16.76 % Number of position-independent correct words: 907 Position-independent word error rate (PER): 15.07 % Results when unknown-word marks (stars) are not removed ------------------------------------------------------- Edit distance: 179 Word Error Rate (WER): 16.76 % Number of position-independent correct words: 907 Position-independent word error rate (PER): 15.07 % Statistics about the translation of unknown words ------------------------------------------------------- Number of unknown words which were free rides: 0 Percentage of unknown words that were free rides: 0%
Sources
I used the online Yulghun dictionary and Uyghurche-Türkche Lughet of E. N. Necip for the vocabulary. For grammar reference, I used Rıdvan Öztürk's Yeni Uygur Türkçesi Grameri.
Future Plans
For a more satisfactory translation and analysis, more disambiguation and lexsel rules must be added. Morphological analysis can be extended to cover the vast non-standard forms of modern Uyghur. With some work on coverage and transfer rules, Tur->Uig translation can be made possible.
