MULTEXT-East Version 4:
Multilingual Morphosyntactic Specifications, Lexicons and Corpora
Tomaž Erjavec
Department of Knowledge Technologies, Jožef Stefan InstituteJamova cesta 39, SI-1000 Ljubljana, Slovenia
tomaz.erjavec@ijs.si
Abstract
The paper presents the fourth, “Mondilex” edition of the MULTEXT-East language resources, a multilingual dataset for language engineering research and development, focused on the morphosyntactic level of linguistic description. This standardised and linked set ofresources covers a large number of mainly Central and Eastern European languages and includes the EAGLES-based morphosyntactic
specifications; morphosyntactic lexica; and annotated parallel, comparable, and speech corpora. The fourth release of these resources
introduces XML-encoded morphosyntactic specifications and adds six new languages, bringing the total to 16: to Bulgarian, Croatian,Czech, Estonian, English, Hungarian, Romanian, Serbian, Slovene, and the Resian dialect of Slovene it adds Macedonian, Persian,Polish, Russian, Slovak, and Ukrainian. This dataset, unique in terms of languages covered and the wealth of encoding, is extensively
documented, and freely available for research purposes at http://nl.ijs.si/ME/V4/.

1.

Introduction

The MULTEXT-East project, (Multilingual Text Tools andCorpora for Eastern and Central European Languages) ran
from ’95 to ’97 and developed standardised language resources for six CEE languages (Dimitrova et al., 1998),
as well as for English, the ’hub’ language of the project.
The main results of the project were morphosyntactic
specifications, defining the tagsets for lexical and corpus annotations in a common format, lexical resources
and annotated multilingual corpora. In addition to delivering resources, a focus of MULTEXT-East was also theadoption and promotion of encoding standardization. On
the one hand, the morphosyntactic annotations and lexica were developed in the formalism used for six Western European languages in the MULTEXT project (Ide andVéronis, 1994), itself based on the EAGLES specifications(http://www.ilc.cnr.it/EAGLES/home.html). On the other,
all the corpus resources were encoded in SGML, according to the Corpus Encoding Standard.
After the completion of the EU MULTEXT-East project, anumber of other projects have helped to keep the MUL TEXT-East resources up-to-date (e.g., migrating the corpus
from SGML to XML) and enabled the addition of new languages; the last release of the resources was Version 3 (Erjavec, 2004), which contains resources for 10 languages.
The MULTEXT-East resources have been instrumental inadvancing the state-of-the-art in language technologies in a
number of areas, e.g., part-of-speech tagging (Tufiş, 1999),
inductive learning of lemmatisation rules (Erjavec andDžeroski, 2004), and word sense disambiguation (Ide et al.,2002), to mention just a few. The morphosyntactic specifications have also become a de-facto standard for a number of languages, e.g., Romanian, Croatian and Sloveneand people form over 100 institutions have requested useof the resources. The success of the resources is mostly
due to the fact that they are freely available for researchand that they include uniformly encoded basic resources
for processing a large number of languages, for which language resources are still (relatively) scarce. As the lin-

guistic markup has been manually validated and tested inpractice, the resources could serve as a “gold standard”
which enabled other researchers to develop and test theirapproaches to topics in language processing.
The resources also provided a model which languages lacking available basic linguistic resources, such as tagsets, lexica and annotated corpora could link up to, taking a welltrodden path. This aspect of the resources was unexpected
but highly rewarding and gives impetus for continued workon the overall design of the MULTEXT-East resources.
For Version 4 release of the resources, a substantial partof the work was undertaken in the scope of the project
Mondilex. Table 1 gives the grid of the “Mondilex” edition
languages and resources, together with the version number when they were made. As can be seen in the table,
Version 4 adds, to varying degrees, six new languages:
Persian (QasemiZadeh and Rahimi, 2006), Macedonian(Ivanovska et al., 2006), Russian (Sharoff et al., 2008),
and, via Mondilex, Polish (Kotsyba et al., 2009), Ukrainian(Derzhanski and Kotsyba, 2009), and Slovak (Garabı́k etal., 2009). Furthermore, the resources for three languages
have been corrected or enhanced.
Version 4 also brings with it also some structural enhancements. The resources have been (re-)coded to be compliant with the current edition of the Text Encoding Initiative
Guidelines, TEI P5 (TEI Consortium, 2007). For corpus resources this was a largely automatic procedure, unlike thatfor the morphosyntactic specifications. Up to and including Version 3 these specifications have been a LATEX file
suitable for printing and conversion to HTML but not for
direct processing over MSDs and features. For Version 4
the specifications have been up-translated to (or authoredin) XML, making it much simpler to validate and process
them automatically. The uniform XML encoding integrates
the specifications, lexica and the morphosyntactically annotated corpus, making it possible to easily move between different representations of the same data. This development
was largely tied to the development of the JOS monolingual Slovene corpora (Erjavec et al., 2010), where the MSD

Language
EnglishRomanian
PolishCzech
SlovakSloveneResianCroatian
SerbianRussian
Ukrainian
Macedonian
Bulgarian
PersianEstonian
Hungarian

FamilyGermanic
RomanceWest Slavic
West Slavic
West Slavic
South West Slavic
dialect of SloveneSouth West Slavic
South West Slavic
East Slavic
East Slavic
South East Slavic
South East Slavic
Indo-IranianFinno-Ugric
Finno-Ugric

MSD
Specs
V1
V1
V4
V1
V4
V1/V4
V3/V4
V2
V2
V4
V4
V4
V1
V4
V1
V1/V4

MSD
Lexicon
V1
V1
V4
V1
V4
V1/V4
V4
V2/V4
V4
V4
V4
V1
V4
V1
V1/V4

1984
MSD
V1
V1
V4
V1
V4
V1/V4
V3
V4∗
V1†
V4
V1
V1

1984
Alignment
N/A
V1
V1
V1
V3
V4
V1
V1
V1

1984
Corpus
V1
V1
V1
V1
V2
V2
V1
V1
V1

Comparable
Corpus
V1
V1
V1
V1
V1
V1
V1

SpeechcorpusV1
V1
V1
V1

Table 1: The MULTEXT-East resources by language, and the version when the resources were made / substantially updated.
MSD specs = morphosyntactic specifications; MSD lexicon = morphosyntactic lexicon (entry = wordform+lemma+MSD);
1984 MSD = MSD and lemma annotated “1984” corpus (* = non-disambiguated; † = automatically tagged with reduced
tagset only); 1984 alignment = sentence alignments with English; 1984 corpus = “1984”, extensively annotated with structural information (poems, quoted speech, etc.) 100,000 words per language; Comparable corpus = fiction and newspaper
structurally annotated corpus, 2 x 100,000 words per language; Speech corpus = parallel speech corpus, 200 sentences per
language, spoken + text.
annotation followed a modified form of the MULTEXT-East
Version 3 MSD tagset, with the intention being that the JOS
morphosyntactic specifications are identical to the Slovene
specifications of MULTEXT-East Version 4.

2.

The Morphosyntactic Specifications

The MULTEXT-East morphosyntactic specifications are
a TEI P5 document that provides the definition of theattributes and values used by the various languages forword-level syntactic annotation, i.e., they provide a formal grammar for the morphosyntactic properties of thelanguages covered. In addition to the formal parts the
specifications also contain commentary, bibliography,
etc. The MULTEXT-East specifications, following theoriginal MULTEXT proposal, define 12 categories (mostly
corresponding to parts-of-speech), each of which thendefines its attributes and their values and the languages
that each particular attribute-value pair is appropriate for.
The morphosyntactic specifications also define the mapping between the feature-structures and morphosyntactic
descriptions (MSDs), which are compact strings used in
the morphosyntactic lexica and for corpus annotation. For
example, they specify that the MSD Ncms is equivalent
to the feature-structure consisting of the attribute-value
pairs Category = Noun, Type = common, Gender= masculine, Number = singular. These definitions
are expressed in the so called common tables, which also
specify for which languages each particular attribute-value
pair is appropriate for. Figure 1 gives an example of an
attribute definition; it is expressed as a table (itself partof the category table) with the role attribute giving thefunction of each row and cell.
The second main part of the specifications are the language
particular sections. These, in addition to the introductory<row role="attribute"><cell role="position">2</cell><cell role="name">Formation</cell><cell><table><row role="value"><cell role="name">simple</cell><cell role="code">s</cell><cell role="lang">bg</cell><cell role="lang">mk</cell><cell role="lang">ru</cell></row><row role="value"><cell role="name">compound</cell><cell role="code">c</cell><cell role="lang">bg</cell><cell role="lang">mk</cell><cell role="lang">ru</cell></row></table></cell></row>

Figure 1: XML encoding of the common tables. Example
gives the definition of the Formation attribute for the Particle category.
matter, also contain sections for each category, with thetable of attribute-value definitions appropriate for the
language. These tables can be automatically derived
form the corresponding common tables, but also modified
from them, a novelty in Version 4. In particular, theposition of the attribute in the MSD can be different
from the common tables, leading to much shorter MSDs
for particular languages. The tables can also containlocalisation information, i.e., the names of the categories,attributes, their values and codes in the particular language,in addition to English. This enables expressing the featurestructures and MSDs either in English, or in the languagein question. For example, they map the English MSD
Ncmsn to the Slovene Somei i.e., samostalnik vrsta= občno ime spol = moški število = ednina
sklon = imenovalnik.

Each language particular section furthermore contains an
index containing all the valid MSDs for the language.
Each MSD can be accompanied by explicative information,e.g., examples of usage. This index is the authority for the
MSD tagset for the language.
An important part of the specifications are the associatedXSLT stylesheets, which allow for various transformations
over the specifications. They take the specifications as input, usually together with certain command line arguments,
and produce either XML, HTML or text output, dependingon the stylesheet.
We provide three classes of transformations, the first ones
to help in adding a new language to the specifications
themselves, the second to transform the specifications into
HTML, and the third to validate and transform a list of
MSDs. The outputs of the second and third class of transforms are included in the distribution. The specifications
rendered in HTML largely follow the formatting of theoriginal LATEX specifications, while various conversions of
the MSD tagsets for each language are provided in a tabularformat for easier use. So, for example, that tables give foreach MSD a canonical expansion into features, a sort-codefor collating the MSDs in “linguist friendly” collation, or
localisation equivalents.

3.

LexicaThe MULTEXT-East morphosyntactic lexicons have a simple structure, where each lexical entry is composed of threefields: (1) the word-form, which is the inflected form of theword, as it appears in the text, modulo sentence-initial capitalisation; (2) the lemma, the base-form of the word; and (3)the MSD, i.e., the morphosyntactic description, which is in
MSDs tagset defined in the appropriate language particularsection.
The size of the lexica between the languages varies considerably, as can be seen in Table 2. Similarly varied are
the number of distinct MSDs and the proportions between
word-forms, lemmas and MSDs. This is not only due to thedifferent properties of the languages, but also to different
approaches adopted in their construction (e.g., including
full inflectional paradigms of the lemmas or only attested
forms), different linguistic traditions, and, in cases, where
the lexicon and MSD tagset were converted from a previous resource, constrains imposed by the automatic mapping
procedure.

4.

The “1984” corpus

A corpus, annotated with context disambiguated MSDs andlemmas, provides the final piece of the “morphosyntactic
triad”, as it contextually validates the specifications and lexicon, and provides examples of actual usage of the MSDs
and lexical items. The parallel corpus included in MUL TEXT-East consists of the novel “1984” by G. Orwell and

Lg
en
ro
pl
cs
sk
sl
slr
sr
ru
uk
mk
bg
fa
et
hu

Entries
71,784
428,093
337,607
184,470
2,461,491
208,002963
412,979
243,765
318,547
1,323,715
54,82313,006135,094
64,003

Words
48,460352,186
174,444
57,246918,668
122,198789
141,509
225,061
205,348
1,236,542
40,546
11,30689,59151,061

Lemmas27,46739,263
13,601
23,28876,224
41,171
338
9,578
46,913
15,162
81,292
22,6206,595
46,93328,063

MSDs
135
616
1,213
1,425
1,534
1,902
518
950
582
1,239
765
338
428
642
827

Table 2: Counts on MULTEXT-East lexica
its translations. The complete novel has about 100,000 tokens, although this of course differs between the languages.
The corpus words are annotated with hand validated MSDs
and lemmas, which makes it suitable for MSD tagging andlemmatisation experiments.
This parallel corpus also comes with separate alignment
files, which contain hand-validated pair-wise sentencealignments (not necessarily 1-1) between English and thetranslations. Version 4 adds pair-wise alignments between
all the languages, automatically induced from the alignments with English.
The MULTEXT-East parallel corpus is, of course, small andconsists of only one text; nevertheless, it provides an interesting experimentation dataset, as there are still few uniformly annotated many-way parallel corpora, esp. of nonWestern European languages.

5.

Related work

Standardisation of multilingual linguistic features usuallyproceeds in the scope of large international projects, andwhile MULTEXT-East has its genesis in such efforts, in particular EAGLES and MULTEXT it has since then proceededby slowly adding new languages and upgrading its representation formalism, without making any revolutionarychanges. In the meantime new initiatives have started witha similar remit, namely to catalogue and standardise morphosyntactic features. We here mention the two most related to the MULTEXT-East, namely GOLD and isoCat, although many other relevant ones exists, mostly as part of
the work of ISO TC 37.
GOLD, the General Ontology for Linguistic Description(Farrar and Langendoen, 2003) is and effort to create
a freely available domain-specific ontology for linguistic
concepts, availabe at http://linguistics-ontology.org/. Given
that this effort is well advanced, and that (morphosyntactic)
terms are extensively documented, also with references toliterature, it would be interesting and not too difficult to link
the categories, attributes and their values form the MUL TEXT-East specifications to GOLD, providing explicationof their semantics.

The isoCat Data Category Registry (Kemps-Snijders et al.,2008) is the Web service at http://www.isocat.org/ implementing the ISO standard 12620:2009 – Terminology andother content and language resources – Specification of data
categories and management of a Data Category Registry for
language resources. It provides an on-line registry, where,
also terms from the domain of morphosyntax can be found.
In the longer term it would be interesting to link up MUL TEXT-East to isoCat (esp. as isoCat used the definitions of
MULTEXT -East V3 in creating its initial registry) but thesystem and procedure is, for now, rather complex.

6.

Conclusions

The paper introduced Version 4 of the MULTEXT-East resources, which are, as their predecessors, freely available for research at the home page of MULTEXT-East, at
http://nl.ijs.si/ME/V4/.
The resources now cover most Slavic languages, which isesp. important as a) for a number of them, language resources are otherwise still hard to find and b) these languages have many common characteristics, i.e., they exhibit complex behaviour on the morphosyntactic level, andthis is the first dataset that enables a qualitative and quantitative comparison between them.
There are a number of obvious areas for further work: to fillin the blanks in the resources for languages that are alreadypart of MULTEXT-East, esp. the annotated “1984” translations and sentence alignments, where these are still lacking.
The number of languages covered could also be extended,most obviously by the Western European languages whichwere already covered by the MULTEXT project, and possibly by other languages that already use MULTEXT-like morphosyntactic specifications.

Acknowledgments
Thanks to Cvetana Krstev, Vladimı́r Petkevič, Radovan Garabı́kand Natalia Kotsyba for comments; for all remaining errors only
the author is to blame. The work presented in this paper was inpart supported by the EU 7FWP under grant agreement 211938
Mondilex “Conceptual Modelling of Networking of Centres forHigh-Quality Research in Slavic Lexicography and their Digital
Resources”.

7.

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