The Hebrew Universal Dependency Treebank: Past, Present and Future
What it is about
The Hebrew Treebank (HTB) grew from 500 newspaper sentences (2001) to 6221 sentences, through a chain of automatic and semi-automatic conversions: phrase structure, then Goldberg's functional-head dependencies, then Unified-Stanford, then UD v1 and UD v2. The authors checked the UD v2 version label by label on the dev set and corrected three kinds of problem: argument types, morphology mixed up with syntax, and language-specific subtypes that duplicate a universal label. The result, UDv2New, changes modal auxiliaries to aux (the following verb becomes xcomp), predicative adjectives to xcomp, prepositional indirect objects to obl, acl:inf to acl, conj:discourse to parataxis, and tokenization of inserted particles. Parsing the dev set with yap under gold morphology raised MLAS from 72.76 to 75.58 and BLEX from 47.76 to 50.16. With automatic morphology the new scheme gave no gain, and it helped only when the correct analysis was injected into the lattice. The authors read this as a lexical-coverage problem, not a scheme problem.
Ideas
- I1. Turn the revised rules into checks: "an
oblfollows a preposition", "noiobjwith anADPchild", "noacl:inf", "anxcompunder a modal verb has anauxhead". Each is a pattern rule with an error or warning level, as in the paper's grewv-style list. Run them ontools/hbooutput. - I2. The paper says the dative (experiencer, ethical, regular) is not separated by UD. Keep the discourse dative as a feature of the argument rather than as a core argument, and test the rule on a small list of Hebrew sentences from
macula compareoutput. - I3. A/B measure: parse one dev set with
tools/hbounder both schemes, with gold and with automatic morphology, two identical runs each. The paper's pattern (gain only with gold or infused lattices) is the expected outcome; if it does not hold, that is a finding. - I4. Modal verbs as a closed list: the paper's
Verb-Type=Modmarking depends on a lexical class. A short table in the Hebrew verb notes, checked against the lexicon.
For Mova
I1 belongs in 11. Modern Hebrew in Universal Dependencies, with the output check in tools/hbo. I2 belongs in Nouns, adjectives, pronouns and numerals and Prepositions, prefixes, conjunctions and particles. I3 is a test for tools/hbo, with its result recorded in 12. Mova and Modern Hebrew: where it stands, what it would need. I4 belongs in 05. The verb: system, binyanim, tense and use.
Cite
@inproceedings{sade2018hebrew,
title = {{The Hebrew Universal Dependency Treebank: Past, Present and Future}},
author = {Sade, Shoval and Seker, Amit and Tsarfaty, Reut},
booktitle = {Proceedings of the Second Workshop on Universal Dependencies (UDW 2018)},
year = {2018},
doi = {10.18653/v1/w18-6016},
url = {https://doi.org/10.18653/v1/w18-6016}
}References
- Meni Adler. 2007. Hebrew Morphological Disambiguation: An Unsupervised Stochastic Word-based Approach. Ph.D. thesis, Ben-Gurion University of the Negev, Beer-Sheva, Israel. find
- Meni Adler, Yael Dahan Netzer, Yoav Goldberg, David Gabay, and Michael Elhadad. 2008. Tagging a hebrew corpus: the case of participles. In LREC. Citeseer. find our card
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