Treebank

In linguistics, a treebank is a parsed text corpus that annotates syntactic or semantic sentence structure. The construction of parsed corpora in the early 1990s revolutionized computational linguistics, which benefitted from large-scale empirical data.^[1]

Most syntactic treebanks annotate variants of either phrase structure (left) or dependency structure (right).

Etymology

The term treebank was coined by linguist Geoffrey Leech in the 1980s, by analogy to other repositories such as a seedbank or bloodbank.^[2] This is because both syntactic and semantic structure are commonly represented compositionally as a tree structure. The term parsed corpus is often used interchangeably with the term treebank, with the emphasis on the primacy of sentences rather than trees.

Construction

Treebanks are often created on top of a corpus that has already been annotated with part-of-speech tags. In turn, treebanks are sometimes enhanced with semantic or other linguistic information. Treebanks can be created completely manually, where linguists annotate each sentence with syntactic structure, or semi-automatically, where a parser assigns some syntactic structure which linguists then check and, if necessary, correct. In practice, fully checking and completing the parsing of natural language corpora is a labour-intensive project that can take teams of graduate linguists several years. The level of annotation detail and the breadth of the linguistic sample determine the difficulty of the task and the length of time required to build a treebank.

Example phrase structure tree for John loves Mary

Hybrid constituency/dependency tree from the Quranic Arabic Corpus

Some treebanks follow a specific linguistic theory in their syntactic annotation (e.g. the BulTreeBank follows HPSG) but most try to be less theory-specific. However, two main groups can be distinguished: treebanks that annotate phrase structure (for example the Penn Treebank^[3] or ICE-GB) and those that annotate dependency structure (for example the Prague Dependency Treebank or the Quranic Arabic Dependency Treebank).

It is important to clarify the distinction between the formal representation and the file format used to store the annotated data. Treebanks are necessarily constructed according to a particular grammar. The same grammar may be implemented by different file formats. For example, the syntactic analysis for John loves Mary, shown in the figure on the right/above, may be represented by simple labelled brackets in a text file, like this (following the Penn Treebank notation):

(S (NP (NNP John))
   (VP (VPZ loves)
       (NP (NNP Mary)))
   (. .))

This type of representation is popular because it is light on resources, and the tree structure is relatively easy to read without software tools. However, as corpora become increasingly complex, other file formats may be preferred. Alternatives include treebank-specific XML schemes, numbered indentation and various types of standoff notation.

Applications

From a computational linguistics^[4] perspective, treebanks have been used to engineer state-of-the-art natural language processing systems such as part-of-speech taggers, parsers, semantic analyzers and machine translation systems.^[5] Most computational systems utilize gold-standard treebank data. However, an automatically parsed corpus that is not corrected by human linguists can still be useful. It can provide evidence of rule frequency for a parser. A parser may be improved by applying it to large amounts of text and gathering rule frequencies. However, it should be obvious that only by a process of correcting and completing a corpus by hand is it possible then to identify rules absent from the parser knowledge base. In addition, frequencies are likely to be more accurate.

In corpus linguistics, treebanks are used to study syntactic phenomena (for example, diachronic corpora can be used to study the time course of syntactic change). Once parsed, a corpus will contain frequency evidence showing how common different grammatical structures are in use. Treebanks also provide evidence of coverage and support the discovery of new, unanticipated, grammatical phenomena.

Another use of treebanks in theoretical linguistics and psycholinguistics is interaction evidence. A completed treebank can help linguists carry out experiments as to how the decision to use one grammatical construction tends to influence the decision to form others, and to try to understand how speakers and writers make decisions as they form sentences. Interaction research is particularly fruitful as further layers of annotation, e.g. semantic, pragmatic, are added to a corpus. It is then possible to evaluate the impact of non-syntactic phenomena on grammatical choices.

In linguistics research, annotated treebank data has been used in syntactic research to test linguistic theories of sentence structure against large quantities of naturally occurring examples.^{[citation needed]}

Semantic treebanks

A semantic treebank is a collection of natural language sentences annotated with a meaning representation. These resources use a formal representation of each sentence's semantic structure. Semantic treebanks vary in the depth of their semantic representation. A notable example of deep semantic annotation is the Groningen Meaning Bank, developed at the University of Groningen and annotated using Discourse Representation Theory. An example of a shallow semantic treebank is PropBank, which provides annotation of verbal propositions and their arguments, without attempting to represent every word in the corpus in logical form.

Language	Treebank	Semantic Formalism	Distribution / License
Chinese	Chinese Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
English	Abstract Meaning Representation (AMR) Bank	Deep semantics	?
English	FrameNet	Shallow semantics	?
English	Universal Conceptual Cognitive Annotation (UCCA)	Deep semantics	?
English	Robot Commands Treebank [6]	Deep semantics	?
English	Groningen Meaning Bank	Deep semantics	different licenses
English	Parallel Meaning Bank	Deep semantics	different licenses
Dutch	Parallel Meaning Bank	Deep semantics	different licenses
German	Parallel Meaning Bank	Deep semantics	different licenses
Italian	Parallel Meaning Bank	Deep semantics	different licenses
English	DeepBank project	Deep semantics	?
English	Treebank Semantics Parsed Corpus	Deep semantics	?
English	RoboCup Corpus	Deep semantics	?
English	Geoquery	Deep semantics	?
English	PropBank	PropBank semantics	different licenses
Finnish	Finnish Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
Finnish	Finnish PropBank	PropBank semantics	CC BY-SA 4.0
French	French Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
German	German Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
Italian	Italian Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
Portuguese	Portuguese PortLex	PropBank semantics	?
Portuguese	Portuguese Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
Spanish	Spanish Universal Propositions	PropBank semantics	CC BY-NC-SA 3.0 US
Turkish	Turkish PropBank	PropBank semantics	CC BY-NC-SA 4.0

Syntactic treebanks

Many syntactic treebanks have been developed for a wide variety of languages:

Language	Treebank	Syntactic Formalism	Distribution / License
Abaza	Universal Dependencies, ATB	Dependency	CC BY-SA
Afrikaans	Universal Dependencies, AfriBooms	Dependency	CC BY-SA
Akkadian	Universal Dependencies, PISANDUB	Dependency	CC BY-SA
Albanian	Universal Dependencies, TSA	Dependency	CC BY-SA
Amharic	Universal Dependencies, ATT	Dependency	CC BY-SA
Ancient Greek	Universal Dependencies, Perseus	Dependency	CC BY-NC-SA
Ancient Greek	Universal Dependencies, PROIEL	Dependency	CC BY-NC-SA
Greek (ancient)	Ancient Greek Dependency Treebank[7][8]	Dependency	Open source (Creative Commons license)
Greek (ancient)	PROIEL Treebank[9]	Dependency	Open source (Creative Commons license)
Arabic	Columbia Arabic Treebank (CATiB)	Dependency	Linguistic Data Consortium
Arabic	Prague Arabic Dependency Treebank (PADT)	Dependency	Linguistic Data Consortium
Arabic	Universal Dependencies, NYUAD	Dependency	CC BY-SA
Arabic	Universal Dependencies, PADT	Dependency	CC BY-NC-SA
Arabic	Universal Dependencies, PUD	Dependency	CC BY-SA
Arabic	Penn Arabic Treebank	Phrase structure	Linguistic Data Consortium
Armenian	Universal Dependencies, ArmTDP	Dependency	CC BY-SA
Assyrian (Neo-Aramaic)	Universal Dependencies, AS	Dependency	CC BY-SA
Bambara	Universal Dependencies, CRB	Dependency	CC BY-SA
Basque	Universal Dependencies, BDT	Dependency	CC BY-NC-SA
Belarusian	Universal Dependencies, HSE	Dependency	CC BY-SA
Bhojpuri	Universal Dependencies, BhEn	Dependency	CC BY-SA
Bhojpuri	Universal Dependencies, BHTB	Dependency	CC BY-SA
Breton	Universal Dependencies, KEB	Dependency	CC BY-SA
Bulgarian	Universal Dependencies, BTB	Dependency	CC BY-NC-SA
Bulgarian	BulTreeBank	HPSG	Freely available for research
Buryat	Universal Dependencies, BDT	Dependency	CC BY-SA
Cantonese	Universal Dependencies, HK	Dependency	CC BY-SA
Catalan	Cat3LB	Phrase structure	Freely available for research
Catalan	Universal Dependencies, AnCora	Dependency	GPL
Chinese	Sinica Treebank	Case grammar	Not freely available
Chinese	Universal Dependencies, CFL	Dependency	CC BY-SA
Chinese	Universal Dependencies, GSD	Dependency	CC BY-SA
Chinese	Universal Dependencies, GSDSimp	Dependency	CC BY-SA
Chinese	Universal Dependencies, HK	Dependency	CC BY-SA
Chinese	Universal Dependencies, PUD	Dependency	CC BY-SA
Chinese	Penn Chinese Treebank	Phrase structure	Linguistic Data Consortium
Chinese	Chinese Dependency Treebank	Dependency	Linguistic Data Consortium
Arabic (classical)	Quranic Arabic Dependency Treebank (QADT) (Quranic Arabic Corpus)	Dependency	Open source (GNU general public license)
Classical Armenian	PROIEL Treebank[9]	Dependency	Open source (Creative Commons license)
Coptic	Universal Dependencies, Coptic Scriptorium	Dependency	CC BY
Croatian	Croatian Dependency Treebank	Dependency	Open source (Creative Commons license)
Croatian	Universal Dependencies, SET	Dependency	CC BY-SA
Czech	Prague Dependency Treebank	Dependency	Open source (Creative Commons license)
Czech	Universal Dependencies, CAC	Dependency	CC BY-SA
Czech	Universal Dependencies, CLTT	Dependency	CC BY-SA
Czech	Universal Dependencies, FicTree	Dependency	CC BY-NC-SA
Czech	Universal Dependencies, PDT	Dependency	CC BY-NC-SA
Czech	Universal Dependencies, PUD	Dependency	CC BY-SA
Danish	Danish Dependency Treebank	Dependency	Open source (GNU general public license)
Danish	Arboretum: A syntactic tree corpus of Danish	Phrase structure	License fee
Danish	Universal Dependencies, DDT	Dependency	CC BY-SA
Danish	Universal Dependencies, DTB	Dependency	CC BY-SA
Dutch	Spoken Dutch Corpus (CGN)	Phrase structure	License fee
Dutch	Universal Dependencies, Alpino	Dependency	CC BY-SA
Dutch	Universal Dependencies, LassySmall	Dependency	CC BY-SA
Dutch	LASSY Small and Large	Dependency	License fee
Dutch	Alpino Treebank	Dependency	Open source (GNU general public license)
Egyptian	Universal Dependencies, UJaen	Dependency	CC BY-SA
English	CCGbank	Combinatory categorial grammar	Linguistic Data Consortium
English	LinGO Redwoods	HPSG	?
English	Lancaster Parsed Corpus	Phrase structure	?
English	Prague English Dependency Treebank	Dependency	Linguistic Data Consortium
English	Universal Dependencies, BhEn	Dependency	CC BY-SA
English	Universal Dependencies, ESL	Dependency	CC BY-SA
English	Universal Dependencies, EWT	Dependency	CC BY-SA
English	Universal Dependencies, GUM	Dependency	CC BY-NC-SA
English	Universal Dependencies, GUMReddit	Dependency	CC BY
English	Universal Dependencies, LinES	Dependency	CC BY-NC-SA
English	Universal Dependencies, ParTUT	Dependency	CC BY-NC-SA
English	Universal Dependencies, Pronouns	Dependency	CC BY-SA
English	Universal Dependencies, PUD	Dependency	CC BY-SA
English	Treebank Semantics Parsed Corpus	Phrase structure	Open source (Creative Commons license)
English	Christine Corpus	Phrase structure	Freely available for research
English	Lucy Corpus	Phrase structure	Freely available for research
English	Susanne Corpus	Phrase structure	Freely available for research
English	BLLIP WSJ corpus	Phrase structure	Linguistic Data Consortium
English	Tübingen Treebank of English / Spontaneous Speech (TüBa-E/S)	HPSG	Freely available for research
English	Diachronic Corpus of Present-Day Spoken English (DCPSE)	Phrase structure	License fee
English	British Component of the International Corpus of English (ICE-GB)	Phrase structure	License fee
English	The PARC 700 Dependency Bank	Dependency	?
English	Yahoo Query Treebank	Dependency	Freely available for research
English	Penn Treebank	Phrase structure	Linguistic Data Consortium
English	Multi-Treebank	Phrase structure	Available online for comparison purposes
English	CHILDES Brown Eve corpus with dependency annotation	Dependency	Open source (Creative Commons license)
English	SMULTRON - Parallel Treebank EN-DE-SV	Phrase structure	Freely available for research
Erzya	Universal Dependencies, JR	Dependency	CC BY-SA
Estonian	Arborest	Phrase structure	?
Estonian	Syntactically analyzed and disambiguated text corpus	Dependency	Freely available for research
Estonian	Universal Dependencies, EDT	Dependency	CC BY-NC-SA
Estonian	Universal Dependencies, EWT	Dependency	CC BY-NC-SA
Faroese	Universal Dependencies, FarPaHC	Dependency	CC BY-SA
Faroese	Universal Dependencies, OFT	Dependency	CC BY-SA
Finnish	Turku Dependency Treebank (TDT)	Dependency	Open source (Creative Commons license)
Finnish	Universal Dependencies, FTB	Dependency	CC BY
Finnish	Universal Dependencies, PUD	Dependency	CC BY-SA
Finnish	Universal Dependencies, TDT	Dependency	CC BY-SA
French (spoken)	Rhapsodie	Dependency and macrosyntactic annotation	Open source (Creative Commons license)
French	L'Arboratoire	Phrase structure	?
French	Universal Dependencies, CrapBank	Dependency	CC BY-SA
French	Universal Dependencies, FQB	Dependency	GPL
French	Universal Dependencies, FTB	Dependency	GPL
French	Universal Dependencies, GSD	Dependency	CC BY-SA
French	Universal Dependencies, ParTUT	Dependency	CC BY-NC-SA
French	Universal Dependencies, PUD	Dependency	CC BY-SA
French	Universal Dependencies, Sequoia	Dependency	GPL
French	Universal Dependencies, Spoken	Dependency	CC BY-SA
French	French Treebank	Phrase structure	Freely available for research
French	Free French Treebank	Phrase structure	Open Source license LGPL-LR
French	Sequoia Treebank	Phrase structure & Dependency	Open Source license LGPL-LR
Galician	Universal Dependencies, CTG	Dependency	CC BY-NC-SA
Galician	Universal Dependencies, TreeGal	Dependency	GPL
German	Hamburg Dependency Treebank (HDT)	Dependency	Freely available for research
German	Universal Dependencies, GSD	Dependency	CC BY-SA
German	Universal Dependencies, LIT	Dependency	CC BY-NC-SA
German	Universal Dependencies, PUD	Dependency	CC BY-SA
German	SMULTRON - Parallel Treebank EN-DE-SV	Phrase structure	Freely available for research
German	NEGRA	Phrase structure	Freely available for research
German	TIGER	Phrase structure	Freely available for research
German	Tübingen Treebank of German / Spontaneous Speech (TüBa-D/S)	Phrase structure	Freely available for research
German	Tübingen Treebank of Written German (TüBa-D/Z)	Phrase structure	Freely available for research
German	Tübingen Partially Parsed Corpus of Written German (TüPP-D/Z)	Phrase structure	License fee
Gothic	PROIEL Treebank[9]	Dependency	Open source (Creative Commons license)
Gothic	Universal Dependencies, PROIEL	Dependency	CC BY-NC-SA
Greek	Greek Dependency Treebank	Dependency	Not freely available
Greek	Universal Dependencies, GDT	Dependency	CC BY-NC-SA
Hebrew	Universal Dependencies, HTB	Dependency	CC BY-NC-SA
Hebrew	Hebrew Dependency Treebank	Dependency	Open source (GNU general public license)
Hindi English	Universal Dependencies, HIENCS	Dependency	CC BY-SA
Hindi	Universal Dependencies, HDTB	Dependency	CC BY-NC-SA
Hindi	Universal Dependencies, PUD	Dependency	CC BY-SA
Hindi	AnnCorra	Dependency	?
English (historical)	Penn Parsed Corpora of Historical English;	Phrase structure	Linguistic Data Consortium (as of April 2020)
English (historical)	York-Toronto-Helsinki Parsed Corpus of Old English Prose (YCOE)	Phrase structure	Freely available for research
French (historical)	Corpus MCVF	Phrase structure	Freely available for research
Portuguese (historical)	Tycho Brahe corpus	Phrase structure	?
Hungarian	Universal Dependencies, Szeged	Dependency	CC BY-NC-SA
Hungarian	Hungarian Treebank	Phrase structure	?
Icelandic	IcePaHC - Icelandic Parsed Historical Corpus	Phrase structure	Open source (GNU Lesser General Public License)
Icelandic	Universal Dependencies, IcePaHC	Dependency	CC BY-SA
Icelandic	Universal Dependencies, PUD	Dependency	CC BY-SA
Indonesian	Universal Dependencies, GSD	Dependency	CC BY-SA
Indonesian	Universal Dependencies, PUD	Dependency	CC BY-SA
Indonesian	ICON	Phrase structure	?
Irish	Universal Dependencies, IDT	Dependency	CC BY-SA
Italian	ISST - Italian Syntactic-Semantic Treebank	Phrase structure and dependency	License fee
Italian	MIDT (Merged Italian Dependency Treebank) resulting from the merging and harmonization of the TUT and ISST-CoNLL/TANL treebanks	dependency	Freely available for research
Italian	VIT - Venice Italian Treebank	Phrase structure and dependency	License fee
Italian	Universal Dependencies, ISDT	Dependency	CC BY-NC-SA
Italian	Universal Dependencies, ParTUT	Dependency	CC BY-NC-SA
Italian	Universal Dependencies, PoSTWITA	Dependency	CC BY-NC-SA
Italian	Universal Dependencies, PUD	Dependency	CC BY-SA
Italian	Universal Dependencies, TWITTIRO	Dependency	CC BY-SA
Italian	Universal Dependencies, VIT	Dependency	CC BY-NC-SA
Italian	Italian Syntactic-Semantic Treebank for the CoNLL-2007 Shared Task (ISST-CoNLL)	dependency	Freely available for research
Italian	SUT - Siena University Treebank	?	?
Italian	TUT - Turin University Treebank	Dependency	Open source (Creative Commons license)
Italian	ISDT (Italian Stanford Dependency Treebank)	dependency	Freely available for research
Japanese	Kyoto Text Corpus	?	?
Japanese	Universal Dependencies, BCCWJ	Dependency	CC BY-NC-SA
Japanese	Universal Dependencies, GSD	Dependency	CC BY-SA
Japanese	Universal Dependencies, KTC	Dependency	CC BY-SA
Japanese	Universal Dependencies, Modern	Dependency	CC BY-NC-ND
Japanese	Universal Dependencies, PUD	Dependency	CC BY-SA
Japanese	Keyaki Treebank	Phrase structure	Open source (Creative Commons license)
Japanese	Tübingen Treebank of Japanese / Spontaneous Speech (TüBa-J/S)	Phrase structure	Freely available for research
Japanese	ATR Dependency corpus	Dependency	?
Karelian	Universal Dependencies, KKPP	Dependency	CC BY-SA
Kazakh	Universal Dependencies, KTB	Dependency	CC BY-SA
Komi Permyak	Universal Dependencies, UH	Dependency	CC BY-SA
Komi Zyrian	Universal Dependencies, IKDP	Dependency	CC BY-SA
Komi Zyrian	Universal Dependencies, Lattice	Dependency	CC BY-SA
Korean	Universal Dependencies, GSD	Dependency	CC BY-SA
Korean	Universal Dependencies, Kaist	Dependency	CC BY-SA
Korean	Universal Dependencies, Penn	Dependency	CC BY-SA
Korean	Universal Dependencies, PUD	Dependency	CC BY-SA
Korean	Universal Dependencies, Sejong	Dependency	CC BY-SA
Korean	Korean Treebank	Phrase structure	Linguistic Data Consortium
Kurmanji	Universal Dependencies, MG	Dependency	CC BY-SA
Latin	Universal Dependencies, ITTB	Dependency	CC BY-NC-SA
Latin	Universal Dependencies, LLCT	Dependency	CC BY-SA
Latin	Universal Dependencies, Perseus	Dependency	CC BY-NC-SA
Latin	Universal Dependencies, PROIEL	Dependency	CC BY-NC-SA
Latin	Index Thomisticus Treebank	Dependency	Open source (Creative Commons license)
Latin	PROIEL Treebank[9]	Dependency	Open source (Creative Commons license)
Latin	Latin Dependency Treebank[10]	Dependency	Open source (Creative Commons license)
Latvian	Universal Dependencies, LVTB	Dependency	CC BY-SA
Lithuanian	Universal Dependencies, ALKSNIS	Dependency	CC BY-SA
Lithuanian	Universal Dependencies, HSE	Dependency	CC BY-SA
Livvi	Universal Dependencies, KKPP	Dependency	CC BY-SA
Magahi	Universal Dependencies, MGTB	Dependency	CC BY-SA
Maltese	Universal Dependencies, MUDT	Dependency	CC BY-SA
Marathi	Universal Dependencies, UFAL	Dependency	CC BY-SA
Mbya Guarani	Universal Dependencies, Dooley	Dependency	CC BY-NC-SA
Mbya Guarani	Universal Dependencies, Thomas	Dependency	CC BY-NC-SA
Middle Irish	Universal Dependencies, CritMITB	Dependency	CC BY-SA
Middle Irish	Universal Dependencies, DipMITB	Dependency	CC BY-SA
Moksha	Universal Dependencies, JR	Dependency	CC BY-SA
Naija	Universal Dependencies, NSC	Dependency	CC BY-SA
North Sami	Universal Dependencies, Giella	Dependency	CC BY-SA
Norwegian	INESS treebanking infrastructure	LFG	?
Norwegian	Universal Dependencies, Bokmaal	Dependency	CC BY-SA
Norwegian	Universal Dependencies, Nynorsk	Dependency	CC BY-SA
Norwegian	Universal Dependencies, NynorskLIA	Dependency	CC BY-SA
Old Church Slavonic	Universal Dependencies, PROIEL	Dependency	CC BY-NC-SA
Old Church Slavonic	TOROT Treebank[9]	Dependency	Open source (Creative Commons license)
Old French	Universal Dependencies, SRCMF	Dependency	CC BY-NC-SA
Old Russian	Universal Dependencies, RNC	Dependency	CC BY-SA
Old Russian	Universal Dependencies, TOROT	Dependency	CC BY-NC-SA
Old Russian	TOROT Treebank[9]	Dependency	Open source (Creative Commons license)
Persian	Persian Dependency Treebank (PerDT)	Dependency	Freely available for research
Persian	PerTreeBank	HPSG	Freely available for research
Persian	Universal Dependencies, Seraji	Dependency	CC BY-SA
Polish	A Treebank / Test Suite for Polish	HPSG	?
Polish	Universal Dependencies, LFG	Dependency	GPL
Polish	Universal Dependencies, PDB	Dependency	CC BY-NC-SA
Polish	Universal Dependencies, PUD	Dependency	CC BY-SA
Polish	Składnica	Phrase structure and Dependency	Open source (GNU general public license)
Portuguese	Universal Dependencies, Bosque	Dependency	CC BY-SA
Portuguese	Universal Dependencies, GSD	Dependency	CC BY-SA
Portuguese	Universal Dependencies, PUD	Dependency	CC BY-SA
Portuguese	Projecto Floresta Sintá(c)tica	Dependency, Phrase structure	Open source (GNU general public license)
Romanian	Romanian Dependency Treebank	Dependency	?
Romanian	Universal Dependencies, Nonstandard	Dependency	CC BY-SA
Romanian	Universal Dependencies, RRT	Dependency	CC BY-SA
Romanian	Universal Dependencies, SiMoNERo	Dependency	CC BY-SA
Russian	Universal Dependencies, GSD	Dependency	CC BY-SA
Russian	Universal Dependencies, PUD	Dependency	CC BY-SA
Russian	Universal Dependencies, SynTagRus	Dependency	CC BY-NC-SA
Russian	Universal Dependencies, Taiga	Dependency	CC BY-SA
Russian	SynTagRus Dependency Treebank (Russian National Corpus)	Dependency	Freely available for research
Sanskrit	Universal Dependencies, UFAL	Dependency	CC BY-SA
Sanskrit	Universal Dependencies, Vedic	Dependency	CC BY-SA
Scottish Gaelic	Universal Dependencies, ARCOSG	Dependency	CC BY-SA
Serbian	Universal Dependencies, SET	Dependency	CC BY-SA
Sindhi	Universal Dependencies, MazharDootio	Dependency	CC BY-SA
Skolt Sami	Universal Dependencies, Giellagas	Dependency	CC BY-SA
Slovak	Universal Dependencies, SNK	Dependency	CC BY-SA
Slovene	Slovene Dependency Treebank	Dependency	Freely available for research
Slovenian	Universal Dependencies, SSJ	Dependency	CC BY-NC-SA
Slovenian	Universal Dependencies, SST	Dependency	CC BY-NC-SA
Spanish	Cast3LB	Phrase structure and dependency	Freely available for research
Spanish	Universal Dependencies, AnCora	Dependency	GPL
Spanish	Universal Dependencies, GSD	Dependency	CC BY-SA
Spanish	Universal Dependencies, PUD	Dependency	CC BY-SA
Spanish	UAM Treebank of Spanish	Phrase structure	Freely available for research
Swedish	Talbanken05	Phrase structure and dependency	Freely available for research
Swedish	Swedish Treebank	Phrase structure	Freely available for research
Swedish	Universal Dependencies, LinES	Dependency	CC BY-NC-SA
Swedish	Universal Dependencies, PUD	Dependency	CC BY-SA
Swedish	Universal Dependencies, Talbanken	Dependency	CC BY-SA
Swedish	SMULTRON - Parallel Treebank EN-DE-SV	Phrase structure	Freely available for research
Swedish Sign Language	Universal Dependencies, SSLC	Dependency	CC BY-SA
Swiss German	Universal Dependencies, UZH	Dependency	CC BY-SA
Tagalog	Universal Dependencies, TRG	Dependency	CC BY-SA
Tagalog	Universal Dependencies, Ugnayan	Dependency	CC BY-NC-SA
Tamil	Universal Dependencies, TTB	Dependency	CC BY-NC-SA
Telugu	Universal Dependencies, MTG	Dependency	CC BY-SA
Thai	NAiST Thai Treebank	Dependency	Open source (GNU general public license)
Thai	Universal Dependencies, PUD	Dependency	CC BY-SA
Thai	THTB	Phrase structure	CC BY 4.0
Turkish	METU-Sabanci Turkish Treebank	Dependency	Freely available for research
Turkish	Universal Dependencies, BOUN	Dependency	CC BY-SA
Turkish	Universal Dependencies, GB	Dependency	CC BY-SA
Turkish	Universal Dependencies, IMST	Dependency	CC BY-NC-SA
Turkish	Universal Dependencies, PUD	Dependency	CC BY-SA
Ukrainian	Institute for Ukrainian, NGO Gold Standard	Dependency	Open source (Creative Commons license)
Ukrainian	Universal Dependencies, IU	Dependency	CC BY-NC-SA
Upper Sorbian	Universal Dependencies, UFAL	Dependency	CC BY-SA
Urdu	NU-FAST Treebank	Phrase structure	Contact at Computational Learning Strategies & Practices
Urdu	The URDU.KON-TB Treebank	Phrase and Hyper Dependency Structure	Contact at Computational Learning Strategies & Practices
Urdu	Universal Dependencies, UDTB	Dependency	CC BY-NC-SA
Uyghur	Universal Dependencies, UDT	Dependency	CC BY-SA
Vietnamese	Universal Dependencies, VTB	Dependency	CC BY-SA
Vietnamese	Vietnamese Treebank	Phrase structure	Freely available for research
Vietnamese	Vietnamese Dependency Treebank	Dependency	Freely available for research
Warlpiri	Universal Dependencies, UFAL	Dependency	CC BY-SA
Welsh	Universal Dependencies, CCG	Dependency	CC BY-SA
Wolof	Universal Dependencies, WTB	Dependency	CC BY-SA
Yoruba	Universal Dependencies, YTB	Dependency	CC BY-SA

To facilitate the further researches between multilingual tasks, some researchers discussed the universal annotation scheme for cross-languages. In this way, people try to utilize or merge the advantages of different treebanks corpora. For instance, The universal annotation approach for dependency treebanks;^[11] and the universal annotation approach for phrase structure treebanks.^[12]

Search tools

One of the key ways to extract evidence from a treebank is through search tools. Search tools for parsed corpora typically depend on the annotation scheme that was applied to the corpus. User interfaces range in sophistication from expression-based query systems aimed at computer programmers to full exploration environments aimed at general linguists. Wallis (2008) discusses the principles of searching treebanks in detail and reviews the state of the art around that time.^[13]

See also

• Text corpus
• Phrase structure grammar
• Dependency grammar
• Parsing
• Part-of-speech tagging