72914225 optimality theory an overview

Optimality Theory: An Overview Nneji, Ogechukwu Miracle

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Optimality Theory: An Overview

NNEJI, OGECHUKWU MIRACLE [email protected] +2348063622121

Department of Linguistics, Igbo and other Nigerian languages

University of Nigeria Nsukka. Abstract The purpose of this paper is to present a general overview of Optimality Theory which was first introduced into phonology in 1993 by Alan Prince and Paul Smolensky but later modified in the same year by McCarthy and Prince. It points out the reason for OT, and analyzes the terms and conditions which it employs. In order to exemplify the applicability of optimality theory, we employed it to account for vowel assimilation, and consonant homorganicity in Igbo. It was observed that just like the relationship between Chomsky’s move-α of 1981 and trace, CON acts as a check in the OT system to prevent illegal operation. The theory which builds on rules which are used at the deep structure to realize the output at the surface structure believes languages’ grammars to be a ranking of constraints. The study establishes the fact that OT is an application of Chomsky’s minimalist program to phonology which has been transferred to other areas of linguistics such as morphology, syntax, pragmatics, and even lexicography. The paper recommends that this theory of minimalism should be used in language studies in order to find out its applicability or otherwise especially to other areas of the Igbo language aside phonology.

Introduction

One currently important and increasingly popular framework - Optimality Theory

(henceforth OT) is a modern approach to phonological analysis that has taken the lead all

over the world. Initiated by Prince and Smolensky (1993) and McCarthy and Prince

(1993), the theory concentrates on the application of Chomsky’s universal grammar in the

analysis of world languages to serve as a new phonological framework that deals with the

interaction of violable constraints. The theory was introduced to be used in phonology, but

it is discovered that recent studies in morphology (Wunderlich, 2004) syntax (Kager,

1999 Ch.8), pragmatics (Blunter and Zeevat, 2004) have also employed its method of

analysis. In recent years, OT has also become the subject of lively interest outside linguistics,

since it is of use today even to the natural and social sciences.

Chomsky’s universal grammar (UG) as observed by Mey (2009) is based on “emically

significant categories in the languages of the world, and suggesting the possible existence

of a universal human reality underlying the particular worlds of diverse cultures”. This

model of grammar was introduced having found out that there are basic underlying


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features which cut across languages and some peculiar to particular languages. These,

Chomsky describes as principles and parameters respectively. In fact, linguistic analyses

after the introduction of UG border around these principles. UG is conceptualized as a

system of (inviolable) principles, which are parameterized to demarcate the space of

possible forms. OT was one of such theories which seek to provide a guide as to the

analysis of UG. Blunter and Zeevat (2004) agree to this when they opine that many

representatives of OT adopt the fundamental distinction between Universal Grammar

(UG) and a language-specific part of Grammar. According to them, the aim of UG is dual

– to describe the innate knowledge of language that is shared by all normal humans, and to

describe the universal properties of language and the range of possible variations among

languages. The language-specific part of grammar typically consists of the lexicon and a

system reflecting the specific structural properties of the language in question. In fact, UG

consists largely of a set of constraints on representational well-formedness out of which

individual languages are formed. By hypothesis, as observed by Kager (2004:1), ‘the

innateness of UG is what makes grammars so much alike in their basic designs, and what

causes the observed developmental similarities’. Rules may differ between languages, but

must always respect a fixed set of universal principles.

This work that presents an overview of optimality theory is divided into sections which

cover the introduction, a brief history of OT, an overview, and applicability of OT to some

aspects of the Igbo language phonology, summary of findings and conclusion.

A Brief History

The history of phonetics and phonology can be traced as back as classical antiquity when

man started making attempts to preserve his speech (which is said to be ephemeral) by

putting it into writing (being more permanent). From the invention of writing systems,

phonology has developed from one stage to the other with each stage introducing its

theories and rules.

The first international congress of linguists which held in The Hague in 1928 is often

viewed as the beginning of phonology set off by the Prague school. Two influential

members of this school are Roman Jakobson (1886-1982) and Prince Nikolay Sergeyevich


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Trubetzkoy (1890-1938). It was this school of phonology that first defined the phoneme,

noted the importance of binary oppositions, and believed that languages are systems.

Sound Pattern of English by Chomsky and Halle (1968) made a radical improvement in

the study of phonology with its formalization of generative phonology (GP). The SPE was

economical in its basic principle, made use of highly abstract underlying forms, discussed

many major issues in the phonology of English including phonotactics, phonological and

stress management in underived, derived and compound words.

Prior to the publication of SPE in 1968, generative phonology has been on ground to

correct the ills of previous phonological theories like glossematics and stratificational

phonology; and prosodic phonology. Its major proponents – Jokobson, Fante, Halle and

Chomsky claim that linguistic description should aim at constructing a grammar that is

capable of generating linguistic forms (see Mbah and Mbah 2000:139 for details).

The problems associated with SPE led to the emergence of Natural Generative Phonology

by Vennemann which was further developed by Hooper in 1976, Natural Phonology by

David Stampe in his doctoral dissertation, Autosegmental Phonology (AP) by John

Goldsmith in 1976 and CV phonology by Khan. Due to the fact that Goldsmith’s AP

concentrates on tone alone and it does not cover other suprasegmental features like stress,

Lieberman’s metrical phonology came as a stress theory to account for languages that are

stress-timed rather than tonal. As at the time of their introduction, each of these theories

solve particular problems but none described languages as a set of constraints hence OT in

the last decade of the 20th century.

Why Optimality?

The early half of the 2oth century witnessed a rule-based approach to researches in

phonology. In rule-based phonology (RBP), a derivation consists of 3 things: an

underlying representation, a surface representation, and a set of rules that connect them.

Major publications of the time like Chomsky and Halle’s (1968) Sound Pattern of English

expressed sound patterns using phonological rules of the form:

1. w → x/y — z;


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where element w turns into another element x, under the conditions made available by y

and z. That is, a rule takes a particular structural description (SD) as its input, and applies

a structural change (SC) to produce the output. OT was proposed as an alternative to the

rule-based framework.

Discussing the motivation for OT, McCarthy (2007) notes that phonological and syntactic

processes are influenced by constraints on the output of the grammar. According to him,

two different kinds of influence can be identified - processes can be blocked by output

constraints; while others can be triggered by output constraints.

OT reclaims traditional grammar's ability to express surface generalizations (e.g.

“syllables must have onsets”, “no nasal+voiceless obstruent clusters”). The mainstream

approach to blocking and triggering is well represented in Chomsky and Lasnik (1977)

with all transformations being optional and meaning preserving.

Phonological rules were considered to be derivational in nature, which means that a good

deal of data was explained by one rule leading to another. This conception of phonology is

focused on inputs or what Chomsky calls ‘underlying form’ and transformations applied to

them. A study of phonological rules in Yawelmani Yokuta, an extinct language of

California by Kisseberth (1970) resulted in what he calls ‘conspiracy’ – three rules collide

in secret to prevent a specific output. An OT grammar avoids such conspiracies by stating

the generalizations directly, as in Two-Level Morphology (Koskenniemi, 1983) or

Declarative Phonology (Bird, 1995). Conspiracy posed a major problem because within

the existing framework, there was no way to express constraints on a grammar’s output.

Sensing this problem, Kisseberth proposed a change in framework necessary rules could

be drastically simplified by removing the information expressed in output constraints.

This idea of output constraint is what led to OT now credited to Alan Prince and Paul

Smolensky. In other words, OT was initiated to remedy the shortfalls of the rule-based

framework which was widely in use before the last ten years of the 20th century. Prince

and Smolensky approached their studies in language from a different standpoint in 1991

and by 1993 presented it to the world in a manuscript entitled Optimality Theory:

Constraint Interaction in Generative Grammar. This paper was reviewed in book form in


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2004 and published by Blackwell Publishing. Today, this approach has popularly come to

be known as ‘Optimality Theory’. Rather than being derivational, where an underlying

representation passes through several stages of change en route the final output, OT is

described as comparative in which output constraints evaluate multiple possible surface

forms simultaneously. Any language can employ OT in the study of its morphology,

phonology, syntax, semantics, sociolinguistics, pragmatics and even historical linguistics.

Though structured in the manner of universal grammar, OT should explain both language-

specific observations and differences between speaking styles, dialects, and different

languages. For a fairly detailed presentation of the history of OT, Nwankwegu (2008) and

Omachonu (2008) are suitable for reference.

Definition of Terms and symbols used in OT

In this section, we present a functional definition of terms usually associated with OT.

Candidates: refer to possible outputs or combinations which are optimal at a particular

time. For example of candidates see tableaux 1-3 below. What necessitates the optimality

of a particular candidate is the context of its use. A candidate is optimal when it satisfies

the whole constraint set or violates a minimal number of constraints and declares any

analysis qualified to be at the top list.

Constraints: The universality of grammar discussed above informs the need to narrow

down the class of universally possible grammars by imposing restrictions on the notions of

‘possible grammatical process’ and ‘possible interaction of processes’, hence constraints.

Constraints are a set of underlying principles that govern transformations. They serve as

checks and balances to transformational analysis. Prince and Smolensky (2004:3) identify

two fundamental classes of constraints: “those that assess output configurations per se and

those responsible for maintaining the faithful preservation of underlying structures in the

output.” These are commonly called faithfulness constraint and markedness constraint. It

should be noted that the type of constraint that apply in one language may not work in

another language. Constraints are ‘violable’. (Kager, 2004) and Oyebade (1998) quoted in

Omachonu reiterate the fact that “constraints are essentially universal and of very general

formulation, with great potential for disagreement over the well-formedness of analysis”.

Constraints are ranked from left to right (highest to lowest). OT bemoans the widely-held


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and age-long view that constraints are language specific. Each language has its own

constraint ranking. The strongest hypothesis, as observed by McCarthy, is that constraint

ranking is the only thing in the grammar that is language-particular: GEN, EVAL, and

even the constraints themselves are universal. What however marks individual grammar in

this model is the order in which these constraints apply.

Input (Lexicon): The lexicon contains the lexical representations (underlying forms) of

the morphemes and supplies the Input for the Generator. Phonological forms of

morphemes are language-specific. There are two levels of representation in OT – the

underlying structure and the surface structure. ‘Input’ refers to the raw materials used in

OT at the underlying structure while ‘output’ stands for what the possible outcome would

be at the structural change. According to McCarthy (2007:2) the deep structure is the

“input to the grammar”.

Output: If two candidates both comply with several constraints, there must be further

(lower-order) constraints which differentiate between the two and select one candidate. If

two candidates cannot be differentiated, they are identical.

☞ The pointing finger identifies the winning or optimal candidate at the output level.

‘!’ indicates a fatal violation for the candidate (so the winning candidate should not have

a ‘!’ in its violation profile).

* The asterisk indicates other forms of violation i.e., it marks violation.

Components of OT

OT has three major components – GEN, CON and EVAL each of which performs a

singular function.

GEN: is the abridged form of GENERATOR. which generates candidates for

comparison. It produces a potentially infinite number of output candidates. For example,

Gen (Input) → {K1, K2, K3, . . . , Kn} and passes them to the EVAL.

CON: which is the short of CONSTRAINT has been discussed above. What CON does is

to run these candidates generated by GEN through a list of violable ranked constraints. A

Constraint is a structural condition, which can either be satisfied by an Output-Form or it


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can be violated. There are three types of constraints: markedness constraints, faithfulness

constraints, and alignment constraints.

Markedness constraints are similar to the surface-structure constraints or filters of the

1970’s. The inventory of markedness constraints in CON is a substantive theory of

linguistic well-formedness — e.g., complex consonant clusters or that-trace sequences are

bad. Markedness constraints may be positively or negatively influenced. It may be positive

when we have such structures as sonorants must be voiced (SONVOICE), syllables must

have an onset (ONSET), or syllables must have a peak (PEAK); and negative when

vowels are not nasalized (*VNASAL), syllables have no coda (NOCODA or *CODA), or

coda obstruents are not voiced (*VOICECODA).

In contrast to markedness constraints which only refer to output forms, faithfulness

constraints are inherently conservative, requiring the output of the grammar to resemble or

even be identical with its input. To be in conformity with the faithfulness constraints, the

output must preserve all segments and preserve their linear order in the output, output

segments must have counterparts in the input, both input and output segments must share

values for voicing. In other words, there should be no elision, metathesis, epenthesis or

even assimilation. Because markedness constraints favour some linguistic structures over

others, they are often in tension with faithfulness constraints, which resist changes to input

structures. This tension is called constraint conflict, and it is resolved in OT by ranking.

Conflict between two markedness constraints or between two faithfulness constraints is

also possible, of course.

The third type of constraint alignment which is not widely discussed stems from the

suggestion of Prince and Smolensky that Lardil forms like // augment to // to

achieve a minimal size while aligning the stem that is root + suffixes with a syllable

boundary.

EVAL: Being the short form of EVALUATOR, EVAL selects one function as the

grammar’s output based on its performance in CON. The Evaluator consists of a set of

ordered constraints: {B1 >> B2 >> . . . Bn} and evaluates the output candidates with

regard to their harmony values that is the extent to which they comply with the constraints.

EVAL selects the optimal of all the candidates generated.


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The Architecture of an OT Grammar

The OT grammar is an input-output model that pairs an output form to an input form. To

achieve this, the grammar contains the division of labour between its components. These

components are usually presented on what is called OT architecture as follows as

presented by de Lacy (2007:9) in Nwankwegu (2008:5).

Figure 1: OT architecture

By way of explaining the above diagram, the GEN derives its input either directly from

the lexicon or from the output of separate syntax module. This is to say that the lexicon

contains the lexical representations of the morphemes and supplies them to GEN which

in turn produces a potentially infinite number of output candidates and still passes them

to EVAL. The EVAL consists of a set of ordered constraints which evaluates the output

candidates with regard to their harmony values that is the degree to which they comply

with the constraints. It is the EVAL that determines the optimal candidate. To work out

or apply the OT architecture discussed above, the tableau (pluralized as tableaux) is often

used. There are two types of tableau – classic tableau and comparative tableau.

Doing OT

Having hypothesized that constraint ranking is the only possible way in which grammars

may differ, it would be more reasonable to agree that the collection of rankings would be

the only justifiable means to a core OT analysis. The optimal candidate is actually the

observed output for any input in the language under analysis. The non-optimal candidate

GEN

EVAL

Interpretive Modules

LEXICON


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which is the loser is GEN-derived from that same input, but it is not the most harmonic

candidate according to EVAL. For EVAL to select the correct candidate as winner,

certain constraints that favour the winner over the loser must dominate every other

constraint that favours the loser over the winner. The logic of this statement follows from

the properties of EVAL. Constraint ranking arguments depend on this logic. There are

three essential elements to a valid ranking argument. First, the constraints to be ranked

must conflict; that is, they must disagree in their assessment of a pair of competing

output candidates derived from the same input. Using vowel assimilation in Igbo as an

instance, the order of ranking for constraints will be:

2. NO HIATUS>>MAX-IO>>DEP-IO>>IDENT-IO

We shall exemplify this using the Igbo compound noun for intestine ‘afqanx’.

Tableau 1

Afq + anx NO HIATUS IDENT-I.O. DEP-I.O. MAX-I.O.

Afqanx * *

Efqanx * *

☞afaanx *

Afanx * *

Ephqanx * *

The order of constraints in 4 proves that OT is not haphazard because it adheres strictly to

ranking of constraints. The constraints used in tableau 1 are detailed below.

NO HIATUS: Adjacent vowels must have the same features.

MAX-I.O: Every element in the input must have a corresponding output.

DEP-I.O: Every element in the output must have a corresponding segment in the

input. On no account should there be insertion.

IDENT-I.O: Every element in the output must have the same feature with its

corresponding input.

When we say that these constraints are in conflict, it is evident in tableau 1 in the sense

that NO HAITUS claims that adjacent vowels must have the same features and IDENT-

I.O claims that every element in the output must have the same features with its

corresponding input, then they are in conflict because for adjacent vowels to have the

same features, output segment and its corresponding input cannot have the same feature.


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The type of constraints used depends on the type of analysis involved. Remember that the

symbol * is used to denote violation. This means that the third candidate which has the

least number of violations is the optimal of the five having incurred the least violation and

satisfies the higher ranked constraints. Its optimality is indicated by the pointing finger.

Again, let us use the Igbo word for ash ‘to see how OT can be applied in consonant

homorganicity in tableau 2.

Tableau 2

ntx ART-I.O MAX-I.O DEP-I.O. IDENT-I.O.

x * * !*

☞ntx *

m tx * *

x * *

In tableau 2, the second candidate ‘ntx is optimal having no violations of the constraints

listed. What it means is that consonant homorganicity insists on the agreement between

places of articulation of adjacent speech sounds. Since ‘t’ is alveolar, it suffices to say

that the most suitable nasal to select for it would be the alveolar nasal ‘n’ not bilabial ‘m’

or velar ‘k’. Insertion of ‘m’ by the first candidate is a fatal violation of the IDENT-IO

constraint. The order of constraint here shall be ART-I.O>>MAX-I.O>>DEP-

I.O>>IDENT-I.O where ART-I.O stipulates that a segment must agree in place of

articulation with its adjacent segment.

Problems with OT

Every theory presents its analysts with special challenges; OT is not an exception at all. In

fact, if the health of an academic theory lies in the liveliness of its controversies, then the

current phonological theory is healthy and clearly in good shape. The present researcher

agrees with Wikipedia (2011) that many criticisms of OT are based on fundamental

misunderstanding of how it works. An example of this is Chomsky’s (1995) claim that

the theory would predict every lexical input to be reduced to a single optimal syllable.

Although McCarthy (being one of the major brains behind the theory intervenes in 1997


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when he explains that universal neutralization of this type (as pointed out by Chomsky

1995) would only be predicted if there were no faithfulness constraints.

Halle (1995) did not mince words in voicing out his observation of OT. According to

him, “...the existence of phonology in every language shows that faithfulness is at best an

ineffective principle that might well be done without.” What he means by phonology is

‘inputs’ and ‘outputs’. It was Prince (2007) who intervened here arguing that markedness

constraint is there to take care of this kind of disparity. Input-output disparity is usually

the result of markedness constraints being ranked above faithfulness constraints (M>>F).

Terminology raises another issue in OT. It is claimed that OT is not technically a theory

in the sense that it does not make falsifiable predictions. The term ‘theory’ as used here is

different from the way it is used in the physical sciences like physics and chemistry

because OT makes falsifiable predictions the same way as other phonological

frameworks. So rather than call it a theory, OT as a framework should better be described

as a scientific paradigm.

One of the shortfalls of OT was its initial sole introduction to phonology although recent

OT studies in other areas such as syntax, morphology, etc have been useful in taking care

of this problem. Selecting or determining the range of possible candidates happens to be

another. Since there are competing candidates, an analyst may have difficulties deciding

which candidate to use and which not to. Owing to the fact that constraints area a

universal phenomenon which languages draw from, Again, introduction of constraints is

another problem which even the present researcher encountered.

Summary and Conclusion

OT posits that language involves constraints, not rules; the constraints are violable, often

the constraints are in conflict; each language ranks the constraints in importance; a

surface form is optimal if it incurs the least serious violations. Grammars must be able to

regulate conflicts between universal constraints, in order to select the ‘most harmonic’ or

‘optimal’ output form. The main innovations of OT can be summarized as follows:

(i) Grammatical constraints can conflict with each other and are violable under

certain conditions.

(ii) Constraints are ranked according to their respective weight.


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(iii) Different rankings of constraints are responsible for differences between

individual grammars or languages.

(iv) A construction is grammatical (not only by virtue of its own properties, or by

virtue of its generative history, but rather) if it wins the competition in a candidate

set, because it satisfies best the higher-ranked constraints.

Summarily, we shall adopt Nwankwegu’s (2008:3) view of OT. According to him OT can be seen

as a linguistic expression of the practical life situation where man is faced with lots of competing

demands being hindered with certain constraints either financial, religious, social, etc. He cannot

achieve anything without violating these constraints. OT is an approach to linguistic analysis that

involves constraints which must be violated to achieve a desired goal.

In conclusion, we regret to say that despite the wide currency of researches in OT, it is yet to be

used extensively in the analysis of corpus in the Igbo language. Even though the present study has

not made any new observation or finding, we recommend that studies in Igbo phonology,

morphology, syntax and other areas of linguistics should adopt an optimality account in order to

find out the applicability or otherwise of the theory to the language.

References

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