Introduction

A richly annotated and genre-diversified language resource, The Prague Dependency Treebank – Consolidated 1.0  (PDT-C in the sequel) is a consolidated release of the existing PDT-corpora of Czech data, uniformly annotated using the standard PDT scheme (albeit not everything is annotated manually, as we describe in detail here).

PDT-corpora included in PDT-C:

• Prague Dependency Treebank (written texts); latest published version 3.5
• Czech part of Prague Czech-English Dependency Treebank (translated data), latest published version 2.0 and 2.0Coref
• Prague Dependency Treebank of Spoken Czech (spoken data); latest published version 2.0
• PDT-Faust (“user-generated“ texts), unpublished data

 

The difference from the separately published original treebanks can be briefly described as follows:

• it is published in one package, to allow easier data handling for all the datasets;
• the data is enhanced with a manual linguistic annotation at the morphological layer and new version of morphological dictionary is enclosed; 
• a common valency lexicon for all four original parts is enclosed;
• a number of errors found during the process of manual morphological annotation has been corrected.

Layers of annotations.  The PDT-annotation scheme has a multi-layer architecture:

• morphological layer (m-layer): all tokens of the sentence get a lemma and morphological tag,
• surface syntax layer (analytical, a-layer): a dependency tree capturing surface syntactic relations such as subject, object, adverbial, etc.,
• deep syntax layer (tectogrammatical, t-layer): capturing the deep syntactic relations, ellipses, valency, topic-focus articulation, and coreference. In the process of the further development of the PDT-scenario, additional semantic annotations (bridging relation, discourse, genre specification, multi-word expressions, etc.) are being added to the original annotation scheme.

In addition to the above-mentioned three (main) annotation layers in the PDT-scenario, there is also the raw text layer (w-layer), where the text is segmented into documents and paragraphs and individual tokens are assigned unique identifiers. There is additional audio and speech recognition layer (z-layer) in the spoken data. In the spoken data part (as opposed to the written corpora), the w-layer is in fact also an “annotated” layer, namely the manually provided transcription of the audio signal.

In order not to lose any piece of the original information, tokens (nodes) at a lower layer are explicitly referenced from the corresponding closest (immediately higher) layer. These links allow for tracing every unit of annotation all the way down to the original text, or to the transcript and audio (in the spoken data). 

Sarančata jsou doposud ve stadiu larev a pohybují se pouze lezením. V tomto období je účinné bojovat proti nim chemickými postřiky, ale dožívající družstva ani soukromí rolníci nemají na jejich nákup potřebné prostředky.

Example sentences from PDT-C 1.0, with tectogrammatical annotation including coreference links (blue and brown arrows), MWEs (red stripes) and discourse annotation (orange arrows and attributes/lables). Lit.: Grasshoppers are still in the larvae stadium, crawling only. At this time of the year, it is efficient to fight them using chemicals, but neither the ailing cooperatives nor private farmers can afford them.

 

In the current PDT-C 1.0 release, manual annotation has been fully performed at the lowest morphological layer; also, basic phenomena of the annotation at the highest deep syntactic layer (structure, functions, verbal valency) have been done manually in all four datasets. Manual annotation of the surface syntactic layer is contained only in the dataset of PDT written texts. Additional semantic features in PDT dataset have been also done manually. Table 1 presents an overview of various types of annotation at the three annotation layers in each dataset and the information of the manner in which the annotations was carried out.

Dataset / Type of annotation	PDT Written	PCEDT (Czech) Translated	PDTSC Spoken	PDT-Faust User-generated
Audio	non-applicable	non-applicable	provided	non-applicable
ASR Transcription	non-applicable	non-applicable	provided	non-applicable
Transcript	non-applicable	non-applicable	manually	non-applicable
Translation	non-applicable	manually	non-applicable	manually
Morphological layer
Speech reconstruction	non-applicable	non-applicable	manually	non-applicable
Lemmatization	manually	manually	manually	manually
Tagging	manually	manually	manually	manually
Surface syntactic layer
Dependency structure	manually	automatically	automatically	automatically
Syntactic function	manually	automatically	automatically	automatically
Clause segmentation	automatically	not annotated	not annotated	not annotated
Deep syntactic layer
Deep syntactic structure	manually	manually	manually	manually
Deep syntactic function	manually	manually	manually	manually
Verbal valency	manually	manually	manually	manually
Nominal valency	manually	not annotated	not annotated	not annotated
Grammatemes	manually	not annotated	not annotated	not annotated
Coreference grammatical	manually	manually	manually	not annotated
Coreference textual	manually	manually	manually	not annotated
Bridging relation	manually	not annotated	not annotated	not annotated
Topic-focus articulation	manually	not annotated	not annotated	not annotated
Discourse	manually	not annotated	not annotated	not annotated
Genre specification	manually	not annotated	not annotated	not annotated
Quotation	manually	not annotated	not annotated	not annotated
Multiword expressions	manually	not annotated	not annotated	not annotated

Table 1: Overview of various types of annotation and their realization in the datasets

Volume of the data

The data volume is given in Table 2. Altogether, the consolidated treebank contains 3,885,591 tokens with manual morphological annotation and 2,245,945 t-nodes with manual deep syntactic annotation (manual annotation of the surface syntactic layer is contained only in the dataset of written texts and it consists of 1,503,741 a-nodes).

	PDT Written	PCEDT (Czech) Translated	PDTSC Spoken	PDT-Faust User-generated	Total
Morphological layer (number of m-forms)	1,957,150	1,152,289	742,316	33,836	3,885,591
Surface syntactic layer (number of a-nodes)	1,503,741	1,152,289	742,316	33,837	3,432,183
Deep syntactic layer (number of t-nodes)	675,034	932,334	608,472	30,105	2,245,945

Table 2. Volume of the datasets (number of tokens on the respective layers)