Dispersion Theory concerns the constraints that govern contrasts, the phonetic differences that can distinguish words in a language. Specifically it posits that there are distinctiveness constraints that favor contrasts that are more perceptually distinct over less distinct contrasts. The preference for distinct contrasts is hypothesized to follow from a preference to minimize perceptual confusion: In order to recover what a speaker is saying, a listener must identify the words in the utterance. The more confusable words are, the more likely a listener is to make errors. Because contrasts are the minimal permissible differences between words in a language, banning indistinct contrasts reduces the likelihood of misperception.
The term ‘dispersion’ refers to the separation of sounds in perceptual space that results from maximizing the perceptual distinctiveness of the contrasts between those sounds, and is adopted from Lindblom’s Theory of Adaptive Dispersion, a theory of phoneme inventories according to which inventories are selected so as to maximize the perceptual differences between phonemes. These proposals follow a long tradition of explaining cross-linguistic tendencies in the phonetic and phonological form of languages in terms of a preference for perceptually distinct contrasts.
Flemming proposes that distinctiveness constraints constitute one class of constraints in an Optimality Theoretic model of phonology. In this context, distinctiveness constraints predict several basic phenomena, the first of which is the preference for maximal dispersion in inventories of contrasting sounds that first motivated the development of the Theory of Adaptive Dispersion. But distinctiveness constraints are formulated as constraints on the surface forms of possible words that interact with other phonological constraints, so they evaluate the distinctiveness of contrasts in context. As a result, Dispersion Theory predicts that contrasts can be neutralized or enhanced in particular phonological contexts. This prediction arises because the phonetic realization of sounds depends on their context, so the perceptual differences between contrasting sounds also depend on context. If the realization of a contrast in a particular context would be insufficiently distinct (i.e., it would violate a high-ranked distinctiveness constraint), there are two options: the offending contrast can be neutralized, or it can be modified (‘enhanced’) to make it more distinct.
A basic open question regarding Dispersion Theory concerns the proper formulation of distinctiveness constraints and the extent of variation in their rankings across languages, issues that are tied up with the questions about the nature of perceptual distinctiveness. Another concerns the size and nature of the comparison set of contrasting word-forms required to be able to evaluate whether a candidate output satisfies distinctiveness constraints.
Matthew K. Gordon
Metrical structure refers to the phonological representations capturing the prominence relationships between syllables, usually manifested phonetically as differences in levels of stress. There is considerable diversity in the range of stress systems found cross-linguistically, although attested patterns represent a small subset of those that are logically possible. Stress systems may be broadly divided into two groups, based on whether they are sensitive to the internal structure, or weight, of syllables or not, with further subdivisions based on the number of stresses per word and the location of those stresses. An ongoing debate in metrical stress theory concerns the role of constituency in characterizing stress patterns. Certain approaches capture stress directly in terms of a metrical grid in which more prominent syllables are associated with a greater number of grid marks than less prominent syllables. Others assume the foot as a constituent, where theories differ in the inventory of feet they assume. Support for foot-based theories of stress comes from segmental alternations that are explicable with reference to the foot but do not readily emerge in an apodal framework. Computational tools, increasingly, are being incorporated in the evaluation of phonological theories, including metrical stress theories. Computer-generated factorial typologies provide a rigorous means for determining the fit between the empirical coverage afforded by metrical theories and the typology of attested stress systems. Computational simulations also enable assessment of the learnability of metrical representations within different theories.
Paul de Lacy
Phonology has both a taxonomic/descriptive and cognitive meaning. In the taxonomic/descriptive context, it refers to speech sound systems. As a cognitive term, it refers to a part of the brain’s ability to produce and perceive speech sounds. This article focuses on research in the cognitive domain.
The brain does not simply record speech sounds and “play them back.” It abstracts over speech sounds, and transforms the abstractions in nontrivial ways. Phonological cognition is about what those abstractions are, and how they are transformed in perception and production.
There are many theories about phonological cognition. Some theories see it as the result of domain-general mechanisms, such as analogy over a Lexicon. Other theories locate it in an encapsulated module that is genetically specified, and has innate propositional content. In production, this module takes as its input phonological material from a Lexicon, and refers to syntactic and morphological structure in producing an output, which involves nontrivial transformation. In some theories, the output is instructions for articulator movement, which result in speech sounds; in other theories, the output goes to the Phonetic module. In perception, a continuous acoustic signal is mapped onto a phonetic representation, which is then mapped onto underlying forms via the Phonological module, which are then matched to lexical entries.
Exactly which empirical phenomena phonological cognition is responsible for depends on the theory. At one extreme, it accounts for all human speech sound patterns and realization. At the other extreme, it is little more than a way of abstracting over speech sounds. In the most popular Generative conception, it explains some sound patterns, with other modules (e.g., the Lexicon and Phonetic module) accounting for others. There are many types of patterns, with names such as “assimilation,” “deletion,” and “neutralization”—a great deal of phonological research focuses on determining which patterns there are, which aspects are universal and which are language-particular, and whether/how phonological cognition is responsible for them.
Phonological computation connects with other cognitive structures. In the Generative T-model, the phonological module’s input includes morphs of Lexical items along with at least some morphological and syntactic structure; the output is sent to either a Phonetic module, or directly to the neuro-motor interface, resulting in articulator movement. However, other theories propose that these modules’ computation proceeds in parallel, and that there is bidirectional communication between them.
The study of phonological cognition is a young science, so many fundamental questions remain to be answered. There are currently many different theories, and theoretical diversity over the past few decades has increased rather than consolidated. In addition, new research methods have been developed and older ones have been refined, providing novel sources of evidence. Consequently, phonological research is both lively and challenging, and is likely to remain that way for some time to come.
Reduplication is a word-formation process in which all or part of a word is repeated to convey some form of meaning. A wide range of patterns are found in terms of both the form and meaning expressed by reduplication, making it one of the most studied phenomenon in phonology and morphology. Because the form always varies, depending on the base to which it is attached, it raises many issues such as the nature of the repetition mechanism, how to represent reduplicative morphemes, and whether or not a unified approach can be proposed to account for the full range of patterns.
Daniel Currie Hall
The fundamental idea underlying the use of distinctive features in phonology is the proposition that the same phonetic properties that distinguish one phoneme from another also play a crucial role in accounting for phonological patterns. Phonological rules and constraints apply to natural classes of segments, expressed in terms of features, and involve mechanisms, such as spreading or agreement, that copy distinctive features from one segment to another.
Contrastive specification builds on this by taking seriously the idea that phonological features are distinctive features. Many phonological patterns appear to be sensitive only to properties that crucially distinguish one phoneme from another, ignoring the same properties when they are redundant or predictable. For example, processes of voicing assimilation in many languages apply only to the class of obstruents, where voicing distinguishes phonemic pairs such as /t/ and /d/, and ignore sonorant consonants and vowels, which are predictably voiced. In theories of contrastive specification, features that do not serve to mark phonemic contrasts (such as [+voice] on sonorants) are omitted from underlying representations. Their phonological inertness thus follows straightforwardly from the fact that they are not present in the phonological system at the point at which the pattern applies, though the redundant features may subsequently be filled in either before or during phonetic implementation.
In order to implement a theory of contrastive specification, it is necessary to have a means of determining which features are contrastive (and should thus be specified) and which ones are redundant (and should thus be omitted). A traditional and intuitive method involves looking for minimal pairs of phonemes: if [±voice] is the only property that can distinguish /t/ from /d/, then it must be specified on them. This approach, however, often identifies too few contrastive features to distinguish the phonemes of an inventory, particularly when the phonetic space is sparsely populated. For example, in the common three-vowel inventory /i a u/, there is more than one property that could distinguish any two vowels: /i/ differs from /a/ in both place (front versus back or central) and height (high versus low), /a/ from /u/ in both height and rounding, and /u/ from /i/ in both rounding and place.
Because pairwise comparison cannot identify any features as contrastive in such cases, much recent work in contrastive specification is instead based on a hierarchical sequencing of features, with specifications assigned by dividing the full inventory into successively smaller subsets. For example, if the inventory /i a u/ is first divided according to height, then /a/ is fully distinguished from the other two vowels by virtue of being low, and the second feature, either place or rounding, is contrastive only on the high vowels. Unlike pairwise comparison, this approach produces specifications that fully distinguish the members of the underlying inventory, while at the same time allowing for the possibility of cross-linguistic variation in the specifications assigned to similar inventories.
Timothy J. Vance
The term rendaku, sometimes translated as sequential voicing, denotes a morphophonemic phenomenon in Japanese. In a prototypical case, an alternating morpheme appears with an initial voiceless obstruent as a word on its own or as the initial element (E1) in a compound but with an initial voiced obstruent as the second element (E2) in a two-element compound. For example, the simplex word /take/ ‘bamboo’ and the compound /take+yabu/ ‘bamboo grove’ (cf. /yabu/ ‘grove’) begin with voiceless /t/, but this morpheme meaning ‘bamboo’ begins with voiced /d/ in /sao+dake/ ‘bamboo (made into a) pole’ (cf. /sao/ ‘pole’). Rendaku was already firmly established in 8th-century Old Japanese (OJ), the earliest variety for which extensive written records exist, and subsequent sound changes have made the alternations phonetically heterogeneous. Many OJ compounds with eligible E2s did not undergo rendaku, and the phenomenon remains pervasively irregular in modern Japanese. There are, however, many factors that promote or inhibit rendaku, and some of these appear to influence native-speaker behavior on experimental tasks. The best known phonological factor is Lyman’s Law, according to which rendaku does not apply to E2s that contain a non-initial voiced obstruent. Many theoretical phonologists endorse the idea that Lyman’s Law is a sub-case of the Obligatory Contour Principle, which rules out identical or similar units if they would be adjacent in some domain. Other well-known factors involve vocabulary stratum (e.g., the resistance to rendaku of recently borrowed E2s) or the morphological/semantic relationship between E2 and E1 (e.g., the resistance to rendaku of coordinate compounds). Some morphemes are idiosyncratically immune to rendaku. Other morphemes alternate but undergo rendaku in some compounds while failing to undergo it in others, even though no known factor is relevant. In addition, many individual compounds vary between a form with rendaku and a form without, and this variability is often not reflected in dictionary entries. Despite its irregularity, rendaku is productive in the sense that it often applies to newly created compounds. Many compounds, of course, are stored (with or without rendaku) in a speaker’s lexicon, but fact that native speakers can apply rendaku not just to existing E2s in novel compounds but even to made-up E2s shows that rendaku as an active process is somehow incorporated into the grammar.
Harry van der Hulst
The subject of this article is vowel harmony. In its prototypical form, this phenomenon involves agreement between all vowels in a word for some phonological property (such as palatality, labiality, height or tongue root position). This agreement is then evidenced by agreement patterns within morphemes and by alternations in vowels when morphemes are combined into complex words, thus creating allomorphic alternations. Agreement involves one or more harmonic features for which vowels form harmonic pairs, such that each vowel has a harmonic counterpart in the other set. I will focus on vowels that fail to alternate, that are thus neutral (either inherently or in a specific context), and that will be either opaque or transparent to the process. We will compare approaches that use underspecification of binary features and approaches that use unary features. For vowel harmony, vowels are either triggers or targets, and for each, specific conditions may apply. Vowel harmony can be bidirectional or unidirectional and can display either a root control pattern or a dominant/recessive pattern.
When the phonological form of a morpheme—a unit of meaning that cannot be decomposed further into smaller units of meaning—involves a particular melodic pattern as part of its sound shape, this morpheme is specified for tone. In view of this definition, phrase- and utterance-level melodies—also known as intonation—are not to be interpreted as instances of tone. That is, whereas the question “Tomorrow?” may be uttered with a rising melody, this melody is not tone, because it is not a part of the lexical specification of the morpheme tomorrow. A language that presents morphemes that are specified with specific melodies is called a tone language. It is not the case that in a tone language every morpheme, content word, or syllable would be specified for tone. Tonal specification can be highly restricted within the lexicon. Examples of such sparsely specified tone languages include Swedish, Japanese, and Ekagi (a language spoken in the Indonesian part of New Guinea); in these languages, only some syllables in some words are specified for tone. There are also tone languages where each and every syllable of each and every word has a specification. Vietnamese and Shilluk (a language spoken in South Sudan) illustrate this configuration. Tone languages also vary greatly in terms of the inventory of phonological tone forms. The smallest possible inventory contrasts one specification with the absence of specification. But there are also tone languages with eight or more distinctive tone categories. The physical (acoustic) realization of the tone categories is primarily fundamental frequency (F0), which is perceived as pitch. However, often other phonetic correlates are also involved, in particular voice quality. Tone plays a prominent role in the study of phonology because of its structural complexity. That is, in many languages, the way a tone surfaces is conditioned by factors such as the segmental composition of the morpheme, the tonal specifications of surrounding constituents, morphosyntax, and intonation. On top of this, tone is diachronically unstable. This means that, when a language has tone, we can expect to find considerable variation between dialects, and more of it than in relation to other parts of the sound system.
Marilyn May Vihman
Child phonological templates are idiosyncratic word production patterns. They can be understood as deriving, through generalization of patterning, from the very first words of the child, which are typically close in form to their adult targets. Templates can generally be identified only some time after a child’s first 20–50 words have been produced but before the child has achieved an expressive lexicon of 200 words. The templates appear to serve as a kind of ‘holding strategy’, a way for children to produce more complex adult word forms while remaining within the limits imposed by the articulatory, planning, and memory limitations of the early word period. Templates have been identified in the early words of children acquiring a number of languages, although not all children give clear evidence of using them. Within a given language we see a range of different templatic patterns, but these are nevertheless broadly shaped by the prosodic characteristics of the adult language as well as by the idiosyncratic production preferences of a given child; it is thus possible to begin to outline a typology of child templates. However, the evidence base for most languages remains small, ranging from individual diary studies to rare longitudinal studies of as many as 30 children. Thus templates undeniably play a role in phonological development, but their extent of use or generality remains unclear, their timing for the children who show them is unpredictable, and their period of sway is typically brief—a matter of a few weeks or months at most. Finally, the formal status and relationship of child phonological templates to adult grammars has so far received relatively little attention, but the closest parallels may lie in active novel word formation and in the lexicalization of commonly occurring expressions, both of which draw, like child templates, on the mnemonic effects of repetition.
Corpus Phonology is an approach to phonology that places corpora at the center of phonological research. Some practitioners of corpus phonology see corpora as the only object of investigation; others use corpora alongside other available techniques (for instance, intuitions, psycholinguistic and neurolinguistic experimentation, laboratory phonology, the study of the acquisition of phonology or of language pathology, etc.). Whatever version of corpus phonology one advocates, corpora have become part and parcel of the modern research environment, and their construction and exploitation has been modified by the multidisciplinary advances made within various fields. Indeed, for the study of spoken usage, the term ‘corpus’ should nowadays only be applied to bodies of data meeting certain technical requirements, even if corpora of spoken usage are by no means new and coincide with the birth of recording techniques. It is therefore essential to understand what criteria must be met by a modern corpus (quality of recordings, diversity of speech situations, ethical guidelines, time-alignment with transcriptions and annotations, etc.) and what tools are available to researchers. Once these requirements are met, the way is open to varying and possibly conflicting uses of spoken corpora by phonological practitioners. A traditional stance in theoretical phonology sees the data as a degenerate version of a more abstract underlying system, but more and more researchers within various frameworks (e.g., usage-based approaches, exemplar models, stochastic Optimality Theory, sociophonetics) are constructing models that tightly bind phonological competence to language use, rely heavily on quantitative information, and attempt to account for intra-speaker and inter-speaker variation. This renders corpora essential to phonological research and not a mere adjunct to the phonological description of the languages of the world.