1. Prague Dependency Treebank 2. 0 Zdeněk Žabokrtský Dept
Prague Dependency Treebank 2.0 Zdeněk Žabokrtský Dept. of Formal and Applied Linguistics Charles University, Prague

2. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

3. Introduction treebank Prague Dependency Treebank
syntactically annotated corpus
(“bank” of syntactic trees)
Prague Dependency Treebank
collection of linguistically annotated Czech texts (2MW), software tools and documentation
morphological and surface- and deep-syntactic dependency-oriented sentence analyses

4. About Czech western group of Slavic languages
rich inflectional morphology
(relatively) free word order language
Latin alphabet extended with accents
(příliš žluťoučký kůň)
spoken in the Czech republic
10+ million speakers

5. Historical background and development of PDT
1920’s – Prague Linguistic Circle founded
’s – influential dependency-oriented works of Lucien Tesniere and Vladimír Šmilauer
mid 1960’s – Petr Sgall’s Functional Generative Description
1992 – Penn Treebank
1994 – Czech National Corpus
1995 – PDT started
1998 – PDT 0.5 pre-release
2001 – PDT 1.0 released by LDC
2006 – PDT 2.0 to be released by LDC

6. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

7. Layered annotation scheme
tectogrammatical layer
surface-syntactic dependency tree
analytical layer
morphological layer
morphological lemma and tag associated with each token
word layer
original text, segmented on word boundaries
He would have gone intoforest.

8. M-layer sentence represented as a sequence of tokens
each token lemmatized and tagged (attributes lemma and tag)
15-character long positional morphological tag
1. (main) POS
2. detailed POS
3. gender
4. number
5. case
...

9. A-layer (1) - nodes and edges
sentence represented as a rooted ordered tree with labeled nodes and edges
edges labeled with analytical functions:
dependency relations (Sb, Obj, Adv, Atr)
non-dep. relations (Coord)
auxiliary (functional) nodes (AuxP for prepositions, AuxC for subordinating conjunctions...)
special treatment of coordination constructions

10. A-layer (2) - coordination
intricate interplay between dependency and coordination relations
PDT solution: both conjuncts (members of coordination) and shared modifiers attached below the coordination conjunction (but distinguished from each other by a special attribute is_member)
direct parent vs. effective parent: M M

11. T-layer (1) - nodes t-nodes node attributes
complex typed feature structures
nodes represent autosemantic words
functional words do not have nodes of their own
artificially added nodes (e.g. for pro-drops)
node attributes
tectogrammatical lemma
dependency relation – functor and subfunctor
grammateme attributes (representing morphological meanings)
attributes for topic-focus articulation
attributes for coreference relations

12. T-layer (2) - dependency relations
according to FGD, two types of functors
actants (arguments)
ACT – actor
PAT – patient
ADDR – addressee
EFF – effect
ORIG - origin
free modifiers (adjuncts)
various types of temporal modifiers - TWHEN, TTIL, TSIN...
spatial and directional modifiers – LOC, DIR1, DIR2, DIR3
MEANS, BENeficiary, CAUSe, REGard, EXTent, MATerial, CONDition...
additional functors for representing non-dependency relations
coordinations – CONJ, DISJ, ADVS ...
appositions – APPS
parenthetical constructions - PAR
expressions in foreign language - FPHR

13. T-layer (3) valency
all occurrences of all verbs in t-trees interlinked with the valency lexicon PDT-VALLEX
individual valency frames roughly corresponds to individual senses of the given verb
valency frame ~ a sequence of frame slots, for each of which its functor, obligatority and its possible surface realizations are specified

14. T-layer (3) - coreference
two types of coreference according to FGD
grammatical (verbs of control, relative clauses, reflexive pronouns...)
textual (personal pronouns, incl. elided ones)
coreference in PDT
binary relation between t-nodes
depicted as a “non-tree” arc (arrow)

15. T-layer (4) - grammatemes
t-node attributes representing morphological meanings
motivation
number for nouns, tense for verbs, degree for adjectives, deontic/verb/sentence modality ...

16. T-layer (5) - node typing
presence/absence of a given attribute?
 the need for node typing
two-level hierarchy of t-layer node types used in PDT 2.0:

17. Interlinking the layers
any unit at any layer has a PDT unique ID
neighboring layers connected by top-down pointers

18. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

19. Sources of text texts provided by the Czech National Corpus
7000 articles (or article fragments) from Czech newspapers and journals:
Lidové noviny (daily newspapers)
Mladá fronta Dnes (daily newspapers)
Českomoravský profit (business weekly)
Vesmír (scientific journal)

20. Amount of annotated data
m-layer data
1.96 MW in 116 kS
a-layer data (75 % of m-layer)
1.5 MW in 88 kS
t-layer data (59 % of a-layer)
0.8 MW in 49 kS

21. Division into files 1 XML file per document and annotation layer

22. Train/test data train : devtest : evaltest = 8 : 1 : 1

23. Full vs. sample data sample data
500 sentences
a freely available subset of the full data
converted also to HTML (can be viewed in any WWW browser, no tree editor needed)
the whole PDT 2.0 except for the full data (but including sample data, all tools, docs, and sample data) is available on the web
the full data will be available only to the licensed users who obtain the CD from the Linguistic Data Consortium

24. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

25. Tree editor TrEd general customizable tree editor implemented in Perl
the main editing and browsing tool in the PDT project

26. Batch processing of the data
btred – batch processing version of tred
ntred – networked
(parallelized) version
of btred
$ btred -TNe 'print "$this->{t_lemma}\n"
if $this->parent==$root and
grep{$_->{functor}=~/^DIR/} $this->children()‘
data/sample/*.t.gz -q

27. Netgraph client-server application for on-line PDT search
implemented in Java

28. Tools for post-annotation consistency checking
hundreds of btred scripts of various types:
technical tests
e.g. each sentence contains at least one token
all identifiers are unique, all referred identifiers exist...
m-layer tests
locative (6th case) cannot occur without a preposition
improbable word forms (e.g. imperatives haš, tel)
a-layer tests
not more than one subject in a clause
attributes (afun Atr) should not appear directly below verbs
t-layer tests
surface forms of verb arguments match the specifications in the valency lexicon
relative pronouns in relative clauses should be in agreement with their antecedent (in the sense of grammatical coreference)

29. Tools for automatic annotation
chain of tools for automatic text processing (from a raw text to a-layer trees):
1. sentence segmentation and tokenization
2. morphological analysis
3. morphological disambiguation
4. dependency parsing (adapted Collins)
5. analytical function assignment

30. Tools for format conversions
conversion not only between PDT data formats, but also from other treebanks’ formats
constituency trees from Negra in TrEd:

31. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

32. PDT 2.0 Documentation PDT Guide Annotation guidelines Publications
overview of all parts of PDT 2.0
mirrors the directory structure of the PDT 2.0 CD-ROM
Annotation guidelines
m-layer (~100 pages)
a-layer (~ 250 pages)
t-layer (~ 800 pages)
Publications
conference and journal papers, technical reports, theses ...
Technical documentation (software tools and data formats)

33. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

34. Outline of the talk Introduction Layers of annotation Data
Software tools
Documentation
Tour through the CD-ROM
Final remarks

35. Want to experiment with...
tagging ?
dependency parsing ?
semantic-role labeling ?
frame semantics ?
word-sense disambiguation ?
anaphora resolution ?
information structure ?
...
Use PDT 2.0, it’s all there !!!

36. Annotation scheme not limited to Czech
T-layer in English
T-layer in German
A-layer in German
A-layer in Arabic
A-layer in Slovene
A-layer in Romanian

37. Those involved (some of)

38. Thank you! BTW, anyone interested in beta-testing?