Universal Dependencies on:
[Wikipedia]
[Google]
[Amazon]
Universal Dependencies, frequently abbreviated as UD, is an international cooperative project to create treebanks of the world's languages. These treebanks are openly accessible and available. Core applications are automated text processing in the field of
This analysis shows that ''she'', ''him'', and ''a note'' are dependents of the ''left''. The pronoun ''she'' is identified as a nominal subject (nsubj), the pronoun ''him'' as an indirect object (iobj) and the noun phrase ''a note'' as a direct object (obj) -- there is a further dependency that connects ''a'' to ''note'', although it is not shown. A second example:
This analysis identifies ''it'' as the subject (nsubj), ''is'' as the copula (cop), and ''for'' as a case marker (case), all of which are shown as dependents of the root word ''her'', which is a pronoun. The next example includes an expletive and an oblique object:
This analysis identifies ''there'' as an expletive (expl), ''food'' as a nominal subject (nsubj), ''kitchen'' as an oblique object (obl), and ''in'' as a case marker (case) -- there is also a dependency connecting ''the'' to ''kitchen'', but it is not shown. Note that the copula ''is'' in this case is positioned as the root of the sentence, a fact that is contrary to how the copula is analyzed in the second example just above, where it is positioned as a dependent of the root.
The examples of UD annotation just provided can of course give only an impression of the nature of the UD project and its annotation scheme. The emphasis for UD is on producing cross-linguistically consistent dependency analyses in order to facilitate structural parallelism across diverse languages. To this end, UD uses a universal POS tagset for all languages—although a given language does not have to make use of each tag. More specific information can be added to each word by means of a free morpho-syntactic feature set. The universal labels of dependency links can be specified with secondary relations, which are indicated as a secondary label behind a colon, e.g. nsubj:pass, following th
"universal:extension" format
This example is taken from the articl
here
An alternative convention for showing dependencies is now used, different from the convention above. Since the syntactic functions are not important for the point at hand, they are excluded from this structural analysis. What is important is the manner in which this UD analysis subordinates the auxiliary verb ''will'' to the content verb ''say'', the preposition ''to'' to the pronoun ''you'', the subordinator ''that'' to the content verb ''likes'', and the particle ''to'' to the content verb ''swim''. A more traditional dependency grammar analysis of this sentence, one that is motivated more by syntactic considerations than by semantic ones, looks like this:This structure is (1c) in Osborne & Gerdes (2019) article.
This traditional analysis subordinates the content verb ''say'' to the auxiliary verb ''will'', the pronoun ''you'' to the preposition ''to'', the content verb ''likes'' to the subordinator ''that'', and the content verb ''swim'' to the participle ''to''.
natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
(NLP) and research into natural language syntax and grammar, especially within linguistic typology
Linguistic typology (or language typology) is a field of linguistics that studies and classifies languages according to their structural features to allow their comparison. Its aim is to describe and explain the structural diversity and the co ...
. The project's primary aim is to achieve cross-linguistic consistency of annotation, while still permitting language-specific extensions when necessary. The annotation scheme has it roots in three related projects: Stanford Dependencies,
Google universal part-of-speech tags, and the Interset interlingua for morphosyntactic tagsets.
The UD annotation scheme uses a representation in the form of dependency trees as opposed to a phrase structure trees. At the present time (January 2022), there are just over 200 treebanks of more than 100 languages available in the UD inventory.
Dependency structures
The UD annotation scheme produces syntactic analyses of sentences in terms of the dependencies of dependency grammar. Each dependency is characterized in terms of a syntactic function, which is shown using a label on the dependency edge. For example:
This analysis shows that ''she'', ''him'', and ''a note'' are dependents of the ''left''. The pronoun ''she'' is identified as a nominal subject (nsubj), the pronoun ''him'' as an indirect object (iobj) and the noun phrase ''a note'' as a direct object (obj) -- there is a further dependency that connects ''a'' to ''note'', although it is not shown. A second example:
This analysis identifies ''it'' as the subject (nsubj), ''is'' as the copula (cop), and ''for'' as a case marker (case), all of which are shown as dependents of the root word ''her'', which is a pronoun. The next example includes an expletive and an oblique object:
This analysis identifies ''there'' as an expletive (expl), ''food'' as a nominal subject (nsubj), ''kitchen'' as an oblique object (obl), and ''in'' as a case marker (case) -- there is also a dependency connecting ''the'' to ''kitchen'', but it is not shown. Note that the copula ''is'' in this case is positioned as the root of the sentence, a fact that is contrary to how the copula is analyzed in the second example just above, where it is positioned as a dependent of the root.
The examples of UD annotation just provided can of course give only an impression of the nature of the UD project and its annotation scheme. The emphasis for UD is on producing cross-linguistically consistent dependency analyses in order to facilitate structural parallelism across diverse languages. To this end, UD uses a universal POS tagset for all languages—although a given language does not have to make use of each tag. More specific information can be added to each word by means of a free morpho-syntactic feature set. The universal labels of dependency links can be specified with secondary relations, which are indicated as a secondary label behind a colon, e.g. nsubj:pass, following th"universal:extension" format
Function words
Within the dependency grammar community, the UD annotation scheme is controversial. The main bone of contention concerns the analysis of function words. UD chooses to subordinate function words to content words, a practice that is contrary to most works in the tradition of dependency grammar. To briefly illustrate this controversy, UD would produce the following structural analysis of the sentence given:
This example is taken from the articlhere
An alternative convention for showing dependencies is now used, different from the convention above. Since the syntactic functions are not important for the point at hand, they are excluded from this structural analysis. What is important is the manner in which this UD analysis subordinates the auxiliary verb ''will'' to the content verb ''say'', the preposition ''to'' to the pronoun ''you'', the subordinator ''that'' to the content verb ''likes'', and the particle ''to'' to the content verb ''swim''. A more traditional dependency grammar analysis of this sentence, one that is motivated more by syntactic considerations than by semantic ones, looks like this:This structure is (1c) in Osborne & Gerdes (2019) article.
This traditional analysis subordinates the content verb ''say'' to the auxiliary verb ''will'', the pronoun ''you'' to the preposition ''to'', the content verb ''likes'' to the subordinator ''that'', and the content verb ''swim'' to the participle ''to''.
Notes
References
*de Marneffe, Marie-Catherine, Christopher D. Manning, Joakim Nivre and Daniel Zeman. 2021. Universal Dependencies. In ''Computational Linguistics'' 47(2), 255–308. *de Marneffe, Marie-Catherine, Bill MacCartney and Christopher D. Manning. 2006. Generating Typed Dependency Parses from Phrase Structure Parses. In the Proceedings of the Language Resources and Evaluation Conference (LREC) 2006, 449–454. Genoa. *de Marneffe, Marie-Catherine and Christopher D. Manning. 2008. The Stanford typed dependency representation. Proceedings of the COLING Workshop on Cross-Framework and Cross-Domain Parser Evaluation, 92–97. Sofia. *de Marneffe, Marie-Catherine, Timothy Dozat, Natalia Silvaire, Katrin Haverinen, Filip Ginter, Joakim Nivre, Christopher D. Manning. 2014. Universal Stanford Dependencies: A cross-linguistic typology. In The International Conference on Language Resources and Evaluation (LREC) 2014, 4585–4592. *Nivre, Joakim. 2015. Towards a Universal Grammar for Natural Language Processing. CICLING 2015: 16th International Conference on Intelligent Text Processing and Computational Linguistics, 3-16. *Osborne, Timothy & Kim Gerdes. 2019. The status of function words in dependency grammar: A critique of Universal Dependencies (UD). Glossa: A Journal of General Linguistics 4(1), 17. . *Petrov, Slav, Dipon Das, and Ryan McDonald. 2012. A universal part-of-speech tagset. The International Conference on Language Resources and Evaluation (LREC) 2012, 2089–2096. Istanbul. *Zeman, Daniel. 2008. Reusable tagset conversion using tagset drivers. In The International Conference on Language Resources and Evaluation (LREC) 2008, 213–218. Marrakech. {{Natural language processing Linguistic units Syntax Dependency grammar