Expressing Ability And Willingness: A Study Of Dynamic Modality For Hindi

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आभ्यंतर (Aabhyantar)      SCONLI-12  विशेषांक         ISSN : 2348-7771

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14. Expressing Ability And Willingness: A Study Of Dynamic Modality For Hindi

Kanishka Jain : Department of Linguistics, University of Delhi

Abstract

 Modality in any language is employed to describe situations that can either be real or unreal is the topic of focus in the existing literature on modals. Modality across different languages can be expressed by variety of modal terms and is categorized into various sub-types. This paper however focuses on the modal verbs (e.g. English can) exhibiting dynamic modality, that are found in Hindi language with an aim of answering the following questions: what is the semantics of such constructions, and how this understanding of Hindi modal verbs can be further used in the field of computational linguistics.

1. Proposal

The goal of this paper is to shed light on dynamic modality found in Hindi language. Dynamic modals express abilities (physical or mental), needs and wishes of a subject. The dynamic modality is marked morphologically in Hindi using two distinct verb forms. The semantics of dynamic modals is presented using the possible-world framework. The remainder of this paper is divided into four parts. Section 2 provides a sketch of modality in general. A brief description of the dynamic modals is given in section 3 along with a morphological analysis of dynamic modality for Hindi language. The semantic analysis of Hindi dynamic modals is done in section 4. Based upon the knowledge developed in previous sections, section 4 gives a sketch of how this understanding of dynamic modals can be useful in the field of computational linguistics. Finally the paper is concluded in section 5.

2. Introduction

Modality is a broad term that is used to talk about an event or a number of events that may or may not be real in any natural language by using certain lexicons. It has been described by the scholars or linguists as a device through which humans can express their commitment or belief towards an expression (Saeed 2003) or is concerned with the status of the proposition that describes the event (Palmer 2001). In general, modality is a grammatical feature employed by the speakers of a language to talk about their beliefs, abilities, obligations, requirements, and so on, whereas in semantic study of language it is used to talk about possibility or necessity of events apart from reality. The lexical items that exhibit modality are known as modals. Modals cross-linguistically vary across verbs like can, may, should, might; or adverbs like maybe, possibly, perhaps; or adjectives like possible, impossible, likely and so on. Modality sometimes interacts with mood (like subjunctive, habitual) and is treated as a specific grammatical category found in almost all the natural languages.

Modality or modal meaning can be categorized in different ways according to the needs of linguistic analysis or on the basis of the language in question. Some of these can be discussed below.

A. Realis vs. Irrealis

Realis mood is related to the events that exist in reality or have occurred in reality. The existence of such events is known or are claimed to exist. In contrast irrealis mood is related to events that does not exist in reality or haven‟t occurred in real. These events have potential to exist.

B. Root vs. Epistemic

The difference between epistemic modality and the root modality is another way of distinguishing modality. Linguists have characterized as root those meanings which denote real world obligation, permission or ability and as epistemic those which denote necessity, probability, or possibility in reasoning (Sweetser 1982). Thus, it can be said that modals facilitate to talk about unreal situations by referring worlds that are not real but accessible.

C. Propositional vs. Event

Palmer (2001) has identified two types of modality namely, propositional modality and event modality. Propositional modality is employed by the speakers of a language to express their attitudes towards a proposition in general whereas event modality is used to talk about the occurrence of a particular event depending upon the circumstances that may or may not be controlled by the subject in question. These are further classified as:

The next section presents an overview of dynamic modality in some detail along with examples from different languages.

3. Dynamic modality

3.1 Overview Dynamic modals indicate the ability or the capacity of an agent (or the subject of a proposition) to perform an action, their wishes or desires, and need to do a task. It can also be defined in terms of internal conditioning factors (factors that are internal to the subject or agent of the proposition) i.e. the agent of a proposition has the ability to perform an action or is willing to do so (Palmer 2001). The term has been used by Nuyts (2016) and Portner (2009) as well. It can be further categorized into two categories viz., abilitive modality and volitive modality according to Plamer, whereas for Portner the difference lies in between volitional modality and quantificational modality. The following examples express the dynamic modality in English:

1. She can swim across the river in 5 minutes.

2. She is able to lift a table with one hand.

3. She wants to participate in SCONLI.

In the above examples, (1) and (2) are the instances of abilitive modality i.e. these propositions express the ability or the need to perform an action by using modal terms namely, can and able to whereas example (3) is the case of volitive modality and shows willingness to perform an action by using an modal verb want. To have a better understanding of dynamic modality the next section describes how it is expressed in other languages.

3.2 Cross-linguistic evidence The examples discussed in this section are from German and Bangla (or Bengali). In German modals /kann/ „can‟ and /imstande/ „able‟ describes the ability (as shown in 5 and 6) and in Bangla /paḍe/ „can‟ and /čae/ „want‟ carry dynamic modal meaning; cf. (7) and (8). German

4. Ich kann Gitarre spielen

I can guitar play „I can play guitar.‟

5. Ich bin imstande, Gitarre zu spielen

I am able guitar to play „I am able to play guitar.‟ Bangla

6. Sita ɛk minəte car mayl dɔəḍta paḍe

Sita one minute four mile run can „Sita can run four miles in one minute.‟

7. Sita ɛk minəte car mayl dɔəḍta cae

Sita one minute four mile run want „Sita wants to run four miles in one minute.‟ It is evident from the above set of examples dynamic modals are common grammatical category observable in most of the natural languages. 3.3 A brief description of Hindi dynamic modals In this section I will describe the morphological properties of dynamic modals found in Hindi language with relevant examples. As discussed in section 3.1 dynamic modality describes the mental or physical capability of the subject of a proposition. In Hindi /sək/ and /cɑh/ are the two modals that signal the presence of dynamic modality in a sentence construction. Here is a selection:

8. vəh teẓ dɔḍ sək-tii hɛ

PRO.3.SG fast runs MOD-HAB.SG.F AUX.PRS.SG „She can/is able to run fast.

In the above example (8) modal /sək/ is an abilitive modal which takes a habitual aspect marker /-ta/, or /-tii/ or /-te/ (vary according to the PNG features involved).To express the willingness in Hindi the verb cɑh‚ „want‟ is used which is also marked with habitual aspect marker /-ta/, or /-tii/ or /-te/ (vary according to the PNG features involved). Consider the following example (9):

9. vəh dilli ʏniivərsitii mẽ pəḍ-nɑ cɑh-tii

PRO.3.SG Delhi University in study-INF MOD-HAB.SG.F hɛ AUX.PRS.SG „She wants to study in Delhi University.‟

4. Semantic analysis of Hindi dynamic modals

4.1 General The goal of this section is to provide a semantic analysis of dynamic modality in Hindi language within the framework of possible world semantics. The term possible worlds in semantics are used for worlds that are real or imaginary. As a preliminary to this goal, I will first define two important related concepts – necessity and possibility. Lyons (1977: 787) considers necessity and possibility as the central notions of traditional modal logic. A proposition is necessarily true if and only if it is true in all the situations and is never false, whereas a possibly true proposition is true in at least one situation. Logicians generally try to draw a distinction between a necessarily true or possibly true proposition („p‟) where possibility and necessity are inverses of each other. These are represented as:

 □: Necessity modal operator

 ◊: Possibility modal operator

4.2 Formalism 4.2.1 Frames, accessibility relation, and models The framework that I am using here is the revised version of traditional modal logic proposed by Portner (2009). According to him the modal logic is essential to the semantics of modals in natural language by drawing distinction between a necessarily true proposition and possibly true proposition. In addition he has proposed to assign an accessibility relation to the propositions. To understand the accessibility relation it is important here to understand and to define other primary concepts related to it. Let us first look at frames and models.

 A frame F is composed of two elements. The first element is a set W. The members of this set W are known as possible worlds say W = {w1, w2, w3, w4, w5...}. The second element is relation R among the member of the set W say R (w1, w1); R(w1, w2); R(w1, w3); R(w1, w4,); R(w1, w5); R(w2, w1); and so on. Simply a frame can be understood as a pair, F = < W, R >. A frame can be of different types namely, reflexive frame, symmetrical frame, serial frame, transitive frame and an equivalence frame.

 A model M is again a pair of two elements viz., a frame F and a valuation function V, i.e. M = < F, V >or M = <<W,R >,V >. The valuation function V assigns truth-value (1/T or 0/F) to each pair of a member of W and a sentence of modal logic. The truth value (1 or 0) of a proposition p in the world w on the model M is indicated by [[p]]wM or [[p]]w, <<W,R >,V >.

Using the above two notions the two modal operators □ and ◊ can be redefined. According to Portner these two operators are defined in terms of “accessible from”. Based upon the relation R, an accessibility relationship exists between the members of W. For e.g. A certain world w1 is said to be accessible from w iff R(w, v). Thus, R is also known as an Accessibility Relation. Therefore,

 [[□p]]w,M implies that a proposition p is true in all members of W accessible from w, otherwise p is false.

 [[◊p]]w,M implies that a proposition p is true for some member of W accessible from w, otherwise p is false.

Given the basic knowledge of frames, models, valuation and accessibility relation let us now define them in terms of possible worlds. A possible world as discussed is a set or group of all the worlds apart from just the real world that can exist in future and/or that has existed in the past c.f. 4.1. The accessibility relation in possible worlds framework will be defined in terms of an individual‟s knowledge. We have R (w, wʹ) iff everything that some individual i knows in w is true in wʹ. For instance to analyse epistemic modality, we will have an “epistemic accessibility relation” R and an “epistemic frame” F as shown in (10), taken from Portner (2009:22).

10. Epistemic frame

F = <W, R > is an epistemic frame iff for some individual i:

 W = the set of possible worlds conceivable by humans.

 R = the relation which holds between two worlds w and wʹ iff everything which i knows in w is also true in wʹ.

4.2.2 Interaction of semantics and modal logic A semantic inquiry of modal sentences focuses on investigating the meaning across languages. This evaluation of meanings of a modal sentence presents a precise account of linguistically driven facts and generalizations. Thus, when linguists, here semanticians employ logic their aim is to provide logically correct account of linguistic facts and generalizations. Hence, it is important that while providing a linguistic analysis of an expression one must look at other significant categories like tense and deictic concepts. Why tense? There are two main reasons for accounting tense or time while investigating modality firstly, modality is often over generalized or categorized as tense and secondly, what is true for an individual now may not be true later for the same individual. Thus, it is important define modality in terms of time as well, as discussed in (11), from Portner (2009:39).

11. Epistemic accessibility relation

R is an epistemic accessibility relation iff, for some individual i and some time t, R = the relation which holds between two worlds w and wʹ iff everything which i knows at t in w is also true in wʹ. What are deictic concepts (also known as indexical concepts)? Portner has defined them as “elements in natural language whose meanings make essential reference to the situation in which they are used, the context of utterance”. Further, there are two levels of meanings – “character” and “context”. The character is the speaker of the modal proposition p whereas the context is the situation in which p is uttered. These two levels of meanings can be formulated by using an accessibility relation function, which is defined as:

12. Accessibility relation function [Portner 2009:41]

A is an accessibility relation function iff

 Its domain is a set of actual and/or hypothetical contexts of utterance, and

 Its range is a set of accessibility relations.

The above discussed accessibility relation function can have sub-categories according to the type of modality for e.g. epistemic accessibility relation function, deontic accessibility relation function, and so on. On the basis of these accessibility relation function(s) we can again define accessibility relation. Therefore an epistemic accessibility relation given in (11) will be:

13. Epistemic accessibility relation (revised)

R is an epistemic accessibility relation iff for any worlds w and wʹ, any individual i and any time t, A = the relation which holds between <w, i, t > and wʹ iff everything i knows in w at t is true in wʹ. The truth value (1 or 0) of a proposition p in the world w on the model M is indicated by [[p]]w,c <<W, A> ,V>. The above brief sketch of properties of modal logic describes all the relevant concepts needed for the examination of Hindi dynamic modals. 4.3 An analysis of dynamic modals An example of Hindi dynamic modal is given in (14). sək contributes to the modality reading of this proposition, while tii is an aspectual marker. Sita is the subject and the context of the utterance is the one where the subject of proposition is able to play basketball.

14. Sita bɑskitbɔl khel sək-tii hɛ

Sita.3.SG basketball plays MOD-HAB.SG.F AUX.PRS.SG „Sita can/is able to play basketball.‟ Here I demonstrate that sək is an abilitive modal. A detailed sketch of (14) is presented in terms of modal logic below. Let us first define an abilitive frame,

15. Abilitive frame for

F = <W, R > is an abilitive frame iff for Sita:

 W = the set of possible worlds conceivable by humans.

 R = the relation which holds between two worlds w and wʹ iff Sita‟s ability to play basketball in w is also true in wʹ.

The next step is to define an abilitive accessibility relation function to express the meaning of the proposition.

16. Abilitive accessibility relation function

A is an abilitive accessibility relation function iff

 A is an accessibility relation function, and

 For every context c in the domain of A, A(c) = the relation which holds between two worlds w and wʹ iff the ability of fI (us) to play basketball at fnow(c) in w is also true in wʹ.

(Here fI (us) = Sita) Here, we have analysed abilitive dynamic modal sək in terms of possible world semantics using the modal logic.

5. A proposal of computational analysis of dynamic modals

In this section I am producing a proposal to analyse the Hindi dynamic modals. The framework that I have used for it is LFG based on the modal logic discussed in the previous section. The LFG theory of grammar as discussed by Joan Bresnan and Ronald Kaplan in 1970's produces two levels of information. For a given proposition Level 1 produces constituent structures (or c-structures) that are basically the tree construction giving language specific information like word order of the language and level 2 produces functional structures (f-structures) expresses language universal information of grammatical functions like subject, object, etc. The structures produced by LFG can be further used in text annotation under the broad area of natural language processing (NLP) for a particular language. These structures are also useful in writing a grammar to produce tree structure (precisely c-structures) in NLP. Conclusion This work basically focussed on the dynamic modal auxiliaries found in Hindi language. I have examined two different types of modal auxiliaries and have proposed an analysis within the possible world semantics using modal logic. The two modals sək and cɑhiye gives dynamic modal meaning to the proposition. Further, it has been proposed that this analysis can be extended to encode the meaning of the modals in NLP by using an LFG model of grammar.

References

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