Ontology of Esperanto Documentation
ReleaseEpistematica

Jul 23, 2017

Contents

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Project scope
1.1 A formal representation of Esperanto’s grammar . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 The OWL-DL ontology of Esperanto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Ontology
2.1 Download the ontologies from GitHub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Paper «Esperanto Ontology»
3.1 Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Ontologies and Description Logics (DL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Esperanto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5 Approaching the project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6 Scheme of the ontologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6.1
Ontology of grammatical analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6.2
Ontology of logical analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6.3
Ontology of period analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7 Considerations on the work done . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8 Perspectives and hypotheses on the future of this type of ontology . . . . . . . . . . . . . . . . . . .
3.9 Correlated products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.10 Bibliography and webgraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Ontology of Esperanto Documentation, Release

The Tower of Babel, Pieter Bruegel the Elder, 1563
Ontology of Esperanto is a research project performed in 2006 by Epistematica.
Table of contents

Contents

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Contents

CHAPTER

1

Project scope

A formal representation of Esperanto’s grammar
This project comes from the question: which could be the best natural language for vocal interaction between humans
and computers?
Esperanto was therefore considered, an artificial language officially born in 1887 for pleasure and thanks to the workof Polish Doctor Ludwik Lejzer Zamenhof, a passionate linguistics studier that wanted to develop a language purelyinternational. From this, Esperanto was adopted by a significant community of speakers in all the world really able tomaintain a serious conversation in this language. The choice of Esperanto was thanks simplicity and regularity of its
grammar that could makes easier for computing systems to manage the structure of the language.
The project “Ontology of Esperanto” is proposed as one of the first attempts to produce a formal representation of anon formal language (natural language), based on the Semantic Web standards.
The goal was to develop an ontology usable into NLP software tools that can make easy a computer understand thelogical form of varying complexity phrases expressed in Esperanto. From here we can imagine a scenario whichon the Semantic Web becomes available innovative services that allow users perform queries in natural language foraccessing data and documents, without having any expertise in formal query languages.

The OWL-DL ontology of Esperanto
Ontology is written in OWL-DL, a version of the language recommended by the W3C for the Semantic Web, using
Protégé, the ontology editor developed by the University of Stanford (US), that uses the automated reasoning servicesof Racer, the semantic reasoner developed by the University of Luebeck (D).
The ontology verily are three: first for the grammar analysis, second for the logical analysis and thitd for the analysisof the sentence, where the highest level ontology refers to concepts at lower levels. In this way, once the various partsof the text is qualified at lower levels, so the higher levels can be automatically inferred.

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Ontology

Download the ontologies from GitHub• Grammar Analysis• Logical Analysis• Period Analysis

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Chapter 2. Ontology

CHAPTER

3Paper «Esperanto Ontology»

Authors Marco Romano1 Luca Severini2
Version latest

Preface
Interest in Esperanto has gone through various phases in Italian culture during the last century. Initially it was ofa humanistic nature and counted Bruno Migliorini, unforgettable president of the Crusca Academy and Alessandro
Bausani, in the writer’s opinion, the best Italian orientalist of all time, amongst it’s Honorary Fellows as well as manyother lesser-known Honorary Fellows among linguists and men of letters. Over the last few decades, has emerged a
new interest more orientated towards possible application of Esperanto in computing. In the 1980s there was intense
activity in the formation of a dependance grammar of Italian for the Distributed Language Translation Project realised
by a Dutch company, BSO, supported by the European Community and having Esperanto as its internal translation
pivot language. Lecturers from the universities of and also participated.
Tullio de Mauro allures to this kind of possibility when he recently wrote “Esperanto today sees openings for real
perspectives of use” in his introduction to a new edition of the Esperanto Manual by Bruno Migliorini (Milan:
OCEDES, 1995). In the end, the same concept was represented by Francesco Sabatini, currently president of the
Crusca Academy; he evokes a concept that the network magazine, summarises thus: “. . . the president of the Crusca
Academy has a proposal in the interests of both people in computing and Esperantists. Opting for a common languagemeans understanding each other better and accelerates development”.
The world of Esperanto speakers cannot but agree on many such opinions. Indeed, they are aware that all affirmations
concerning the easiness and regularity of Esperanto, and man’s use of it, are inferior to what Esperanto really offers.
No other language studied in a formal manner and by adults can be mastered like Esperanto; it’s easiness and regularity
quickly allow it to become a second mother tongue or at the least a second language that can be used as automaticallyas a mother tongue. This is what, more than people in computing and linguists, the poets have been saying for a
century, by means of their contribution to the creation of considerable original and translated literature in Esperanto.
1 PhD in Logics and Informatics
2 Founder of Epistematica, holder of the research project7

Ontology of Esperanto Documentation, Release

Personally, as an Esperanto speaker interested in the psycho-linguistic phenomena that occur in the mind of a speakerof this language and others, I cannot but wish great success to this new project on Esperanto Ontology which united
logical rigour with extremely advanced technical knowledge.
Prof. Renato Corsetti - Psycho-linguist, Department of Psychology, University of Rome Sapienza

Objectives
The Esperanto Ontology project presents itself as one of the first attempts to produce a formal description of a nonformal language by means of innovative tools such as ontologies for the semantic web.
Indeed, by virtue of these it is possible to exploit the expressive richness of logic to obtain a symbolic description of
any known dominion onto which inferential-deductive automatic reasoning can be sustained. This type of reasoning on
its own is not evidently sufficient to comprehend the whole functioning of a natural language, spoken by “semanticallyomnipotent” human beings and therefore capable of meaning anything through language, given that the human mind
uses other forms of reasoning (capacity of abstraction, singling out pertinence between concepts, reasoning by images
and association of ideas etc.) in order to master such a tool; it is, in any case, an important opportunity to increase
the possibilities of recognising the logical form3 of a proposition on the part of a computer. The fact that this process
makes queries expressed in natural language comprehensible to a computer is of particular interest to us for producing
a formal description.
Our objective was exactly that of building a tool by virtue of which logical forms of phrases of varying complexity
in Esperanto could be recognised by a computer. From here we can start to imagine an applicative scenario in which
innovative services are available on the web which can be interrogated by users in a natural language, without the needfor them to be competent in database interrogation languages.
A wider horizon for this work can be integrated in the Epistematica project, proposed as a high-level interface forcomputer communications managed by software reasoners.

Ontologies and Description Logics (DL)Classic ontology is a formal description in any known dominion that is capable of showing a hierarchy of concepts
inherent to the matter (by means of taxonomy) and the relationships between them (by means of a series of properties
defined for each concept): an ontology for the semantic web also has the characteristic of being written in a particularlanguage that can be “read” (not) by human beings but by external computing applications.
The appropriate language for an ontology is a logical language capable of guaranteeing the formalism of the description to be produced; the language chosen by the World Wide Web Consortium (W3C) as standard for semantic web
ontologies is the Ontology Web Language (OWL) of which there are 3 varieties: Full, DL and Light. OWL-Full is a“good translation” of the classic Logic of the First Order (FOL) language which, however, carries the limit of semidecidibility, that is to say, the impossibility of guaranteeing complete automatic reasoning owing to the fact that it
can express propositions capable of sending the computer into a “loop” and blocking its reasoning. OWL-Light is the“poor” variety which does not cause problems to automatic reasoning but only permits very reduced expressiveness.
OWL-DL however, is greatly plentiful in expressiveness which, even though reduced respect to OWL-Full, is enoughnecessary to contain expressiveness in the dominion of decidibility and therefore to guarantee complete automatic reasoning. The DL suffix stands for Description logic. Various description logics were developed during the 1970s, each
one with different expressive characteristics and potentialities; it is from these that even more languages were built,
distinguished for use of logic in the environment of knowledge management computing, an environment in which tools
must be powerful enough not only to profoundly describe knowledge but also to guarantee a complexity of finishedcalculation to render knowledge really useful.
3 Logical form of a proposition means it’s logical structure, recognised by assigning appropriate roles of subject, predicate, object etc. to theparts that compose it.

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Thanks to the OWL-DL language, we can realise an integrated system which uses ontologies as instruments for representation of knowledge and a programme named “software reasoner” for developing deductive reasoning beginningwith encoded knowledge with the guarantee that reasoning will be complete.

Esperanto
Esperanto does not originate from a community of speakers, but was designed, it is an artificial language officiallycreated in 1887 by the will and works of the Polish doctor Zamenhof, a passionate scholar who wanted to develop apurely international language. Since then Esperanto has been adopted by a consistent community of speakers (there
are about 250 thousand Esperantists in the world) which have “brought it to life” from the artificial language that it
was to huge enrichment and, inevitably, exposing it to the constant mutation of natural languages. In any case if on
the one side, once built, Esperanto has been brought to life precisely because it was designed to behave like a natural
language to all effects, on the other it conserves the elegance of total regularity of its grammar which is a rare caseamong natural languages
The reasons for choosing Esperanto for this project are therefore evident and pertain to at least two distinguishedorders: on one side because Esperanto was born from an ambitious project to build a universal language which allmen could use in equal competence, the language itself guaranteeing equal dignity to its speakers by putting them allon the same level as Esperanto is nobody’s mother tongue; on the other because it is particularly easy to describe in acomplete manner thanks to its grammatical characteristics, both morphological and syntactic ones.

Approaching the project
The technology chosen to produce our basis of knowledge of Esperanto is therefore that of ontologies for the semantic
web because we can flank to these a software reasoner, a programme born from research on Artificial Intelligenceable to conduct logical inferences starting from expressions of Description logic. The ontology-reasoner combination
generates the possibility of dynamically enriching the basis of knowledge, easily keeping it updates and, most of all,comparing the knowledge described in it to that coming from other bases. The tools that we used were precisely thefreeware interface Protégé (version 3.1 with OWL-Plugin developed by Stanford University) for writing ontologies
in OWL language and the software reasoner RacerPro (version 1.8 manufactured by RacerSystems) for verifying
integrity and coherence of ontologies, which is also available as a reasoner for practical realisation of applications
based on these ontologies.
There is no univocal, better or more correct way to describe a dominion of knowledge, therefore there may reasonably
exist more ontologies dedicated to the same subject and each may show their own characteristics and advantages. In
our case we tried to build an ontology that is functional to our purpose and therefore sufficiently slim and elastic inorder for it to be easily used by a software reasoner, but it also need to be powerful enough to supply an interesting,thereby not exhaustive, description of Esperanto even to a human who observes taxonomic structure and accompanying
properties.
In order to proceed with the decomposition and reconstruction of Esperanto in a systematic way, we used an approach“by level of analysis” from which three distinctive ontologies are derived: one for grammatical analysis which supplies a classification of the words according to the typical categories of the parts of speech; and another for logicalanalysis which exploits the sintagma concept to group single words into “logical groups”; and lastly the said level ofanalysis of the period destined to the interpretation of relationships between the larger components of the sentence, thepropositions.
This approach has produced ontologies that are in a hierarchal relationship between them, so that the analysis forthe period explains itself starting with the logical analysis which in turn is comprehended integrating it with thegrammatical one; the use of this technique was permitted by the capability of OWL language to import ontologies thatare distinct from each other.

3.4. Esperanto

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Each of these three ontologies was created using the axiomatic method, this means that undefined terms are used ineach one of these, terms left to intuition as one might say, or better, concepts that are defined somewhere else, in
our case in the parser programme which, in a concrete application of this programme, must instance and accompany
logical reasoning based on ontology. For example, the concept word is not defined by the ontology, but its definition
is in the parser which will recognise and isolate each recognisable sequence of characters as a word according to thedefinition given by its programming; then, by means of ontology, it is possible to identify the various parts of the
speech, all subsumed from the concept word.
The role of the parser to accompany the ontologies is not secondary because not only must it “read” the text at the
beginning of the analysis but it must read it many times, and every time carrying the new knowledge about the text
which the reasoner will have inferred on the basis of the combination of information it has received from previous
readings and from the rules described in the ontologies. Therefore, three sequential reading and reasoning phases areto be considered, enriched from time to time by parser-reasoner interaction until the phrase is completely understood.
The approach followed in this project presents yet another aspect which merits attention: the construction of “layers”
makes sure that only the lowest level, that of grammatical analysis, is completely configured on Esperanto, while
the superior levels can easily be utilised for other natural languages by superimposing them onto a purpose-built
grammatical level.

Scheme of the ontologies
Ontology of grammatical analysis
This is the ontology at the lowest level, it produces classification of words according to the traditional concepts ofSubstantive, Adjective, Pronoun, Verb, Adverb and Preposition which are all subclasses, as specifications, of Word.
The concept of word is the axiom of this level and its operative definition is left to parser programming.
Thanks to the characteristics of Esperanto grammar, the definition of the speech parts is quite simple. Esperanto, in
fact, is a productive language, that is to say it theoretically forms all types of words (i.e. name, adjective, verb etc.)
starting from each semantic root and it characterises the grammatical type using termination so that for each nameends in -o, all qualified adjectives in -a and adverbs in -e. There are, however, particular cases like Pronouns andPrepositions which do not have such a general rule of production and therefore necessitate more specific treatment,
thereby these words, which are a relatively small number, have been manually inserted as instances for respective classof pertinence without an automatic test.
Some of the above-mentioned concepts are furtherly specified: such is the case with the verb, equipped in Esperantowith a series of terminations which univocally characterise each combination of verbal mode and time, following
which an efficient classification of all the verbal options is obtained; it is also the case of the Pronoun, of which all thecategories existing in Esperanto are recorded, and of the Adjective which is defined in a mixed manner: in fact, twoof its subclasses necessitate the same treatment used for the pronouns and prepositions (manual insertion of instances
without the possibility of closing their classes with a general definition) while the other subclass – qualified Adjective– is properly defined exploiting the rule of production for which adjectives generally terminate in -a.
There is an unusual concept in the middle of this traditional classification of the speech parts, the “Accusative Word”.
The utility of inserting this concept into the same level of the speech parts analysis will be clarified later, here it issufficient to be aware that Esperanto does not have a complete flexible system but distinguishes an accusative caseterminating in -n; the concept of the Accusative Word, therefore covers exactly the class of words that occur inaccusative.
Behind the taxonomy of concepts, ontology of grammatical analysis also supplies tools for characterising words
according to gender and number criteria: these are treated as two properties to be evaluated for each word that isrecognised as Substantive, Adjective or Pronoun by the reasoner. Evaluation takes place with the parser programme
operating, once again it will exploit Esperanto peculiarities to recognise words easily. In Esperanto, in fact, each plural
word ends in -j and every female word is built with the -in suffix.

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Ontology of logical analysis
This is a second level ontology as it exploits a few concepts of the ontology regarding grammatical analysis; it also introduces the “sintagma” concept as a new axiom for subtypes for which it supplies generally valid definitions (nominal,
verbal and prepositional sintagma).
In this ontology there are also concepts of logical analysis on the supply of sintagma notions which are Verbal Predicate
and Nominal Predicate, because we think these can produce operative advantages when an application is realised which
will exploit this ontology to translate a query from Esperanto to a computing language.
By using ontology properties, the necessary links between Predicate and Subject, such as those of compliments dependent on a verb, are also introduced in this ontology.
Amongst the compliments the object compliment is outlined for two reasons: the particular role this compliment
generally covers in the grammar of occidental and romance languages and the ease of recognition it has by virtueof the presence of the accusative case (examined at a level of grammatical analysis), the case in which the object
compliment is always formed. Exactly for this reason it was deemed necessary to describe the accusative case on thelevel of grammatical analysis in order to have it as an available concept on this higher level.

Ontology of period analysis
The new axiom of this level is the Phrase concept of which the predicative function is taken into consideration, thatis, to declare a state or relation regarding a subject, neglecting particular cases of phrases at the margins of linguistic
analysis. The subconcept of Predicative Phrase is thereby immediately highlighted while the rest of the analysis
concerns hierarchal relationships among which propositions can be maintained, i.e. semantically incomplete phrases
which together form a period. In actual fact, a period is also a partially defined concept which requires a “raw”
definition that can be utilised by the parser like the axioms of these ontologies.
In the absence of further analysis on the types of proposition (relative, causal, temporal, etc) which could also be
distinguished in Esperanto, ontology at this level is simply implied as a tool for recognising hierarchal structure amonglarger components of the proposition so that the reasoning obtained from this level is mostly exploitable to improve
the obtainable results on the lower level, that of logical analysis, the real heart of this project.

Considerations on the work done
This “ontological collection” intends to describe Esperanto in order to use this language in computing applicationsof various kinds which can range, as mentioned above, from a query translator which facilitates the man-machine
relationship up to its integration in a more ample communications protocol between machine and machine. In any
case, precisely because of the elasticity and available of use that permit a knowledge base like this, the strictly computing side of the construction of software applications which exploit these ontologies for specific purposes assumes
considerable importance.
In fact, these ontologies for Esperanto, apart from the benefits of being built in an integrated manner, therefore exploitable on various levels of analysis and being the first to be produced, also have all the limits from an analyticalpoint of view which derive from the decision to supply a description of Esperanto which is functional to combined use
with a parser. Basically it is neither a grammatical proposal of using Esperanto for humans to learn, nor a model ofcomplete and rigorous language but a description which outlines a good number of rules of Esperanto and, on higher
levels, of the syntaxes in general that are deemed sufficient for an adequately configured programme to obtain the
logical form of phrases written in Esperanto and therefore permit understanding of the phrases when complex systems
dedicated to a particular context are produced; complex systems meaning the “translator” tool, complete with ontologies and parsers, applied over another knowledge base or even a simple database from which a specific ontology is
supplied.

3.7. Considerations on the work done

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Perspectives and hypotheses on the future of this type of ontology
Ontologies written in OWL are tools belonging to the semantic web and their fate, according to the W3C, is that ofgranting a large step forward towards the web as foreseen by Tim Berners Lee where each website, each resource
available on the Net will be described, even through ontologies, in a way that it will have a specific identification not
only for its position which is the purpose of URIs, but also concerning its “being” as one might say in philosophicalterms, or, to be clearer, its value within the context of the Net.
There will be a long wait for this project to come about, until all those giving out information of any kind on the web
realise that by adding an ontology to the resources that they publish, they are contributing to the realisation of semantic
web which will probably be more interesting and certainly more tidy and hospitable than it is today.
Yet, as this project has shown, ontologies seem to be quite useful for other purposes. As they are forms of descriptionsof knowledge, we have used them to produce a knowledge base on Esperanto which does not accompany any resourceson the web4 , but is put forward as a nucleus and starting point for interesting and innovative applications which could
considerably facilitate simply navigation and management, conservation and consultation of information on a web
which is not yet semantic.

Correlated products
Result of this work are three ontologies in OWL-DL format which form a whole with the present paper. These are theontologies:
Note:• EsperantoGrammarAnalysis.owl• EsperantoLogicalSyntagmaticAnalysis.owl• EsperantoPeriodAnalysis.owl

Bibliography and webgraphy
Considering the huge amount of material published both in traditional and electronic format on each of the themes
discussed in this document, the following bibliography is only for indicating some enlightening texts, possibly on
an introductive level or alternatively originating from more authorised sources, on each argument identified by theparagraphs that examine them.
Esperanto:• Amerio F., Bonvecchiato G., Fighiera G.C. (by), Esperanto: Data and Facts, 2nd edition, FEI- Milan 2002
• Migliorini B., Manual on Esperanto, CO.ED.ES – Milan 1995
• We recommend visiting the Italian Esperantist Federation website at http://www.esperanto.it• For researching documents in Esperanto, research in this language is available on Google, http://www.google.
com/intl/eoSemantic Web:• Gregoris A., Van Harmelen F., A Semantic Web Primer, The MIT Press – 2004
4 This could, however, be available on the web as a resource and perhaps accompanied by an ontology which describes it.

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Ontology of Esperanto Documentation, Release• And naturally World Wide Web Consortium documents available at http://www.w3.org/standards/semanticweb/
OWL-DL language:• Costello R.L., Calvanese D., McGuiness D., Nardi D., Patel-Schneider P. (by) The Description Logic Handbook:
Theory, Implementation and Applications, Cambridge University Press – 2003
• Grosof B.N., Horrocks Y., Volz R., Decker S., Description Logic Programs: Combining Logic Programs with
Description Logic, in Proc. 12th Intl. Conf. On the World Wide Web (WWW-2003), May 20-23, 2003
In conclusion, the following are websites relative to the tools that we have used in this project:• Racer, software reasoner - https://www.ifis.uni-luebeck.de/~moeller/racer/• Protégé, ontology editor - http://protege.stanford.edu• Project’s repository on GitHub

3.10. Bibliography and webgraphy13