Adapting the Portuguese Braille System to Formal Semantics
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Adapting the Portuguese Braille System to Formal Semantics Luís Filipe Cunha Faculdade de Letras da Universidade do Porto / Centro de Linguística da Universidade do Porto (Unidade FCT PEst-OE/LIN/UI0022/2011) Via Panorâmica, s/n, 4150-564, Porto, Portugal luisfi[email protected] Abstract account for various aspects of meaning in nat- Since the seminal work of Richard Montague in the ural language. Although the initial task of for- 1970s, mathematical and logic tools have successfully mal semantics was to describe and resolve am- been used to model several aspects of the meaning of biguities regarding quantification in the nomi- natural language. However, visually impaired people continue to face serious difficulties in getting full ac- nal domain, it was rapidly expanded to cover cess to this important instrument. Our paper aims to other areas of interest to semanticists, from present a work in progress whose main goal is to pro- tense and aspect relations (e.g., Dowty, 1979; vide blind students and researchers with an adequate Bach, 1986; Moens, 1987; Parsons, 1990) method to deal with the different resources that are used to complex modal descriptions involving the in formal semantics. In particular, we intend to adapt the Portuguese Braille system in order to accommodate the interaction of time, situations, and possible most common symbols and formulas used in this kind worlds (cf. Portner, 2009 and the papers col- of approach and to develop pedagogical procedures to lected in Kratzer, 2012, for example). facilitate its learnability. By making this formalisation compatible with the Braille coding (either traditional The adoption of formal outlines in the context and electronic), we hope to help blind people to learn of the semantic descriptions for natural lan- and use this notation, essential to acquire a better under- guages has the advantage of giving rise to un- standing of a great number of semantic properties dis- ambiguous representations for the meaning of played by natural language. sentences, which facilitate the confirmation or rejection of the suggested hypotheses and pos- 1 Introduction tulates. In their attempt to describe and understand the To illustrate this point, let us consider a sim- multiple aspects that underlie the construction ple example, classically discussed in the liter- of sentential meaning in natural languages, ature. A sentence like “Every student read a philosophers and semanticists explored dif- book” is clearly ambiguous between two in- ferent conceptions and methodologies, which terpretations: it may mean that every student gave rise to a large number of theoretical ap- read a (non-specific) book, whatever it is; or it proaches. may mean that there is a (specific) book that A fruitful and promising way to tackle some every student read. The formal representations of the most complex semantic problems, based in (1) and (2) unambiguously spell out these on a formal notation, was initiated by Richard two readings: Montague in the decade of 1970 (see e.g., Montague, 1974). Formal approaches to se- mantics use logical and mathematical tools to 1) 8 x, student(x) ! 9 y, book(y) & read(x, y) 7 Proceedings of the First Workshop on Language Technology for Equality, Diversity and Inclusion, pages 7–14 April 19, 2021. ©2020 Association for Computational Linguistics (For every x, if x is a student, then there is a y The variables that may be introduced in a for- which is a book so that x read y) mula correspond to entities of distinct kinds: they can be individuals, intervals of time, situ- 2) 9 y, book(y) & 8 x, student(x) ! read(x, y) ations or (possible) worlds. Besides the pred- (There is a y which is a book and for every x, if x is a student, then x read y) icative relations, entities may interact with a range of operators that include quantifiers, re- lations between elements and sets of elements book) or between two sets of elements, or even prece- dence or overlapping relations in the temporal In other words, in the representation in (1), the domain. universal quantifier has wide scope over the ex- Despite its undeniable relevance regarding the istential one, which leads to the multiple book semantic studies on recent years, no attempt reading. Conversely, in (2), it is the existential has been done, at least to our knowledge, to quantifier that has wide scope over the univer- provide visually impaired people with ade- sal one, giving rise to the unique book reading. quate tools that enable them to learn and man- On the other hand, formal representations have age this kind of formalisation. been able to transcend the domain of simple The main goal of our project is, thus, to ex- sentences. In fact, Kamp & Reyle’s (1993) plore some ways that could make it possible to Discourse Representation Theory (DRT) ex- blind students and researchers to interact with tends the semantic formalisation to more com- the most common and widespread representa- plex discourses and Asher & Lascarides’ tions in formal semantics. To do so, we will (2003) Segmented Discourse Representation make use of the immense potential that is of- Theory (SDRT) even deals with pragmatic- fered to us by the Braille system. based notions such as those underlying Rhetor- 2 The Braille system: some preliminary re- ical Relations. marks Today, formal semantics supports a significant Braille is the most widespread and efficient number of theories that describe meaning in means for blind people to read and write texts. natural language. In fact, formal approaches It was created in France by Louis Braille in cover almost all areas that traditionally are as- 1824 in order to provide a tactile representa- cribed to semantic studies, from simple word tion for the French alphabet (cf. Mellor 2006). relations to the intricacies behind discourse Based on the night writing encoding system structures. developed by Charles Barbier, the Braille sys- Irrespective of the particularities that charac- tem consists of rectangular cells placed se- terise the diverse frameworks departing from quentially. Each cell corresponds to one char- formal approaches to meaning, there are, acter and it is traditionally constituted by two nonetheless, some important principles that columns each of which presents three “slots” . bring them together. In all cases, predicates are The different combinations of salient or raised related to their argument(s), i.e., entities that dots in each cell gives rise to the several Braille fulfil the predicative relation. Different kinds characters. The six dots that form a cell are of operators are introduced in order to model numbered, so that each character can be iden- the interactions that arise between the partici- tified by the raised dots that represent it. For pants in a sentence or even between indepen- instance, the character “b” , in Braille, is iden- dent sentences in a discourse. tified by dots 1 and 2, the character “t” by dots 8 2, 3, 4 and 5, and so on. There are 64 possi- and knowledge easily accessible: it allows ble combinations, including no dots at all for blind persons to access technology and to write spaces between words. and read emails, books, newspapers, and sci- As we have pointed out, the original purpose of entific articles on practically equal terms with the development of the Braille system was to respect to sighted people. provide a tactile transcription of the printed al- Although its use is declining in some parts of phabet, enabling blind people to read and write the world, due mainly to the growing influence texts. Since the languages of the world differ of audio media, such as speech synthesizers, considerably from each other, either concern- Braille remains essential for the learning pro- ing the alphabets that are employed, or regard- cess and for the general literacy of visually im- ing the number and type of graphic accents and paired people, facilitating their inclusion in the punctuation marks they use, Braille encoding labour market and in other important social ac- is language-specific, i.e., it varies according to tivities, especially when it is used in combi- the chosen language. nation with new technologies (see, e.g., Wia- Braille has proven to be an immensely power- zowski 2014). ful and flexible system in various ways. Of course, it was not our intention here to pro- First, it was fruitfully adapted to include vide an in-depth approach to the internal struc- a large number of languages and alphabets ture and functioning of the Braille system, hav- around the world. Moreover, it was extended ing limited ourselves only to leave a few brief to cover other notations. Music, mathemat- remarks on the aspects that seem most relevant ics, physics, chemistry, phonetics, or informat- and more useful to our purposes. For more de- ics are some of the multiple areas in which tails and information, see, among many others, Braille has been successfully employed to Hampshire (1981), Croisdale, Kamp & Werner make knowledge more accessible to visually (2012), Wiazowski (2014), and, for specific as- impaired people (cf. Herlein 1975; Thompson pects of the Portuguese Braille system, Lemos 2005; Schweikhardt et al. 2006; Englebretson & Cerqueira (1996), Baptista (2000), Reino 2009). (2000) or Pereira (2002). Second, Braille has adapted easily to the emer- 3 The project gence of new technologies, following its con- Given that our project is still at an exceedingly tinuous development. The ancient slate and early stage, it will not be possible to offer here stylus – a handwriting device – has been sub- any relevant results and conclusions. Never- stituted by Braille writers, and, more recently, theless, I will expose our main goals and the by refreshable Braille displays, notetakers and methodology that was chosen to achieve them. tablets (cf.