1. Prague Arabic Dependency Treebank
MorphoTrees of Arabic and Their Annotation in the TrEd Environment
Otakar Smrž
Petr Pajas
Center for Computational Linguistics
Institute of Formal and Applied Linguistics
Charles University in Prague

2. MorphoTrees of Arabic and Their Annotation in the TrEd Environment
MorphoTrees … TrEd … ???
MorphoTrees mean turning unorganized sets of complex morphological analyses into hierarchies
Intuitive, decision-efficient, multi-purpose, interesting
In general, not limited to the language, nor the system of morphology, nor the levels, nor the implementation
TrEd is a fully programmable graphical editor for tree-like graphs and an excellent suite of tools for data batch processing (local/network)
Analytical and tectogrammatical dependency annotation
Viewing and converting of Arabic phrase-structure trees
Evaluating and merging of parser/tagger/human results
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

3. MorphoTrees of Arabic and Their Annotation in the TrEd Environment
MorphoTrees in TrEd
Files with two types of trees
Criteria & restrictions
Automatic decisions
Hiding modes
Viewing options
Short-cut keys & mouse
Consist-ency checks
Processing & update macros
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

4. MorphoTrees of Arabic and Their Annotation in the TrEd Environment
Arabic … the Questions
Is there syntactic difference in sawfa ′arā ′abā ′Aḥmada and sa′as′alu wālidahu ? Is there morphological difference?
The only difference is in the use of lexical units and morphs. The grammatical categories are unchanged, and morphology and syntax should clearly show this.
How do we find syntactic units? How do we get back word-forms from the lexical units and tags?
How much does improper morphological reading disturb consequent syntactic representation?
Improper in tags, lemmas, diacritics, or in tokenization?
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

5. MorphoTrees of Arabic and Their Annotation in the TrEd Environment
Reminder of the Terms
Grapheme / Phoneme
The least units capable of distinguishing meanings
~ 40 letters, context-dependent forms
28 consonants, 6 vowels
Morph
Composition of graphemes / phonemes
Abstract derivational forms
Morpheme
The least unit representing some linguistic meaning
Function of morphs
Projection of grammatical categories
Token
The least syntactic unit
Bearer of a uniform vector of grammatical categories
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

6. Tim Buckwalter’s Morphology
PADT MorphoTrees are generated based on the information provided by Buckwalter Arabic Morphological Analyzer
+ Updateable stem-based lexicon, finite-state model, implementation in Perl and published under GNU GPL
– Morphs, mapping only to Quasi-Functional Morphology
The tokenization, clustering, modeling of conditionality, …
(wabijAnibihA) [jAnib_1] wa/CONJ + bi/PREP +
jAnib/NOUN + i/CASE_DEF_GEN + hA/POSS_PRON_3FS C wa
CONJ
and P bi
PREP at
N R
jAnib+i
NOUN+CASE_DEF_GEN
side of
S----3FS2- hA
POSS_PRON_3FS
her
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

7. Xerox Morphological Analyzer
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

8. MorphoTrees Hierarchy
MorphoTrees of Arabic propose these levels
Entity – the analyzed elements of the discourse
Partitioning to the standard forms of the tokens
Non-vocalized standard orthographical forms
Lemmas/identifiers of lexical units
Tokens – syntactic units including the form and the tag
Independence on the language / implementation
More/different levels, inclusion of spelling variations, …
Annotation of various tagsets, other features of tokens
Efficiency of decision-making
Distance between analyses becomes recognized
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

9. MorphoTrees Annotation
Selecting the leaves that correspond to the proper reading of the tokens constituting the entity
Quick use of keyboard and/or mouse for annotations
Restricting the tree according to the criteria/categories required by the context
Natural control over the inheritance of restrictions
Employing automatic restrictions and annotation actions, both generic and linguistic
Learning about the discriminative categories and “human tagging”
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment

10. Discussion and Conclusion
MorphoTrees
Imporant in morphological annotation and in evaluation
PADT 1.0 provides annotated tokens
Functional Morphology
… more in Prague Arabic Dependency Treebank: Development in Data and Tools
Even its approximation is promising and welcome
Feature-Based Tagger trained on Penn ATB 2
3.6% error rate in major part-of-speech (15 values)
10.8% in the full tagset (317 evidenced combinations)
0.8–0.6% error rate in tokenization of the input
September 22, 2004
MorphoTrees of Arabic and Their Annotation in the TrEd Environment