Speakers of most languages comprehend and produce a very large number of morphologically complex words. But how? There is a tension between two facts. First, speakers can comprehend and produce novel words, which they have never experienced and therefore could not have stored in memory. For example, English speakers readily generate the plural form of wug. These novel words often look like they are composed of recognizable parts, such as the plural marker -s. Second, speakers also comprehend and produce many words that cannot be straightforwardly decomposed into parts, such as bought or brunch. Morphology is the paradigm example of a quasi-regular domain, full of only partially productive, exception-ridden patterns, many of which nonetheless appear to be learned and used by speakers and listeners. Quasi-regularity has made morphology a fruitful testing ground for alternative views of how the mind works. Every major approach to the nature of the mind has attempted to tackle morphological processing. These approaches range from symbolic rule-based approaches to connectionist networks of simple neuron-like processing units to clouds of richly specified holistic exemplars. They vary in their assumptions about the nature of mental representations; particularly, those comprising long-term memory of language. They also vary in the computations that the mind is thought to perform; including the computations that are performed by a speaker attempting to produce or comprehend a word. In challenging all major approaches to cognition with its intricate patterns, morphology continues to provide a valuable window onto the nature of the mind.
Number is the category through which languages express information about the individuality, numerosity, and part structure of what we speak about. As a linguistic category it has a morphological, a morphosyntactic, and a semantic dimension, which are variously interrelated across language systems. Number marking can apply to a more or less restricted part of the lexicon of a language, being most likely on personal pronouns and human/animate nouns, and least on inanimate nouns. In the core contrast, number allows languages to refer to ‘many’ through the description of ‘one’; the sets referred to consist of tokens of the same type, but also of similar types, or of elements pragmatically associated with one named individual. In other cases, number opposes a reading of ‘one’ to a reading as ‘not one,’ which includes masses; when the ‘one’ reading is morphologically derived from the ‘not one,’ it is called a singulative. It is rare for a language to have no linguistic number at all, since a ‘one–many’ opposition is typically implied at least in pronouns, where the category of person discriminates the speaker as ‘one.’ Beyond pronouns, number is typically a property of nouns and/or determiners, although it can appear on other word classes by agreement. Verbs can also express part-structural properties of events, but this ‘verbal number’ is not isomorphic to nominal number marking. Many languages allow a variable proportion of their nominals to appear in a ‘general’ form, which expresses no number information. The main values of number-marked elements are singular and plural; dual and a much rarer trial also exist. Many languages also distinguish forms interpreted as paucals or as greater plurals, respectively, for small and usually cohesive groups and for generically large ones. A broad range of exponence patterns can express these contrasts, depending on the morphological profile of a language, from word inflections to freestanding or clitic forms; certain choices of classifiers also express readings that can be described as ‘plural,’ at least in certain interpretations. Classifiers can co-occur with other plurality markers, but not when these are obligatory as expressions of an inflectional paradigm, although this is debated, partly because the notion of classifier itself subsumes distinct phenomena. Many languages, especially those with classifiers, encode number not as an inflectional category, but through word-formation operations that express readings associated with plurality, including large size. Current research on number concerns all its morphological, morphosyntactic, and semantic dimensions, in particular the interrelations of them as part of the study of natural language typology and of the formal analysis of nominal phrases. The grammatical and semantic function of number and plurality are particularly prominent in formal semantics and in syntactic theory.
Computational psycholinguistics has a long history of investigation and modeling of morphological phenomena. Several computational models have been developed to deal with the processing and production of morphologically complex forms and with the relation between linguistic morphology and psychological word representations. Historically, most of this work has focused on modeling the production of inflected word forms, leading to the development of models based on connectionist principles and other data-driven models such as Memory-Based Language Processing (MBLP), Analogical Modeling of Language (AM), and Minimal Generalization Learning (MGL). In the context of inflectional morphology, these computational approaches have played an important role in the debate between single and dual mechanism theories of cognition. Taking a different angle, computational models based on distributional semantics have been proposed to account for several phenomena in morphological processing and composition. Finally, although several computational models of reading have been developed in psycholinguistics, none of them have satisfactorily addressed the recognition and reading aloud of morphologically complex forms.
Olaf Koeneman and Hedde Zeijlstra
The relation between the morphological form of a pronoun and its semantic function is not always transparent, and syncretism abounds in natural languages. In a language like English, for instance, three types of indefinite pronouns can be identified, often grouped in series: the some-series, the any-series, and the no-series. However, this does not mean that there are also three semantic functions for indefinite pronouns. Haspelmath (1997), in fact distinguishes nine functions. Closer inspection shows that these nine functions must be reduced to four main functions of indefinites, each with a number of subfunctions: (i) Negative Polarity Items; (ii) Free-Choice Items; (iii) negative indefinites; and (iv) positive or existential indefinites. These functions and subfunctions can be morphologically realized differently across languages, but don’t have to. In English, functions (i) and (ii), unlike (iii) and (iv), may morphologically group together, both expressed by the any-series. Where morphological correspondences between the kinds of functions that indefinites may express call for a classification, such classifications turn out to be semantically well motivated too. Similar observations can be made for definite pronouns, where it turns out that various functions, such as the first person inclusive/exclusive distinction or dual number, are sometimes, but not always morphologically distinguished, showing that these may be subfunctions of higher, more general functions. The question as to how to demarcate the landscape of indefinite and definite pronouns thus does not depend on semantic differences alone: Morphological differences are at least as much telling. The interplay between morphological and semantic properties can provide serious answers to how to define indefinites and the various forms and functions that these may take on.