Sign languages use space because they can. In previous work on verb agreement in sign languages, we have discussed “the ability of a language produced in space to represent certain spatial and visual concepts iconically” (Aronoff, Meir & Sandler, 2005). We resolved in that work what we called “the paradox of sign language morphology.” Although all sign languages that had been well studied up to that point showed a particular form of complex simultaneous non-affixal verb agreement that has no simple parallel in the morphology of spoken languages, they did not show much “run of the mill” sequential affixal morphology. Why should a language acquire complex morphology before it acquires simple morphology, why sign languages and why this particular sort of morphology? We argued that the agreement morphology of sign languages is based on an iconic use of space, which sign languages accommodate readily, and that this iconicity is what leads to the quick development of the system. Linear affixal morphology, by contrast, is much slower to emerge and much more varied, precisely because it is not iconic.

In this chapter, we will focus a much finer lens on the iconically based grammatical use of space in sign languages. Specifically, we will look at the actual production of verb forms where we expect space to be used. We will compare forms produced across two or three generations of signers of two young sign languages, Al-Sayyid Bedouin Sign Language (ABSL) and Israeli Sign Language (ISL).

Of the three major categories – hand configuration, location, and movement – the hand configuration category is the most complex. The hand has many degrees of freedom, and sign languages exploit this articulatory range, though subject to certain constraints. The four fingers and the thumb can be selected in various combinations in the articulations of handshapes. The fingers can bend at any joint, or at more than one joint at once. The thumb can be adducted or abducted, can contact fingertips, or can close over the fingers. In addition, the whole hand may be oriented in various directions. In this chapter, we present generalizations that have been discovered about the way in which these possibilities are both exploited and constrained in sign languages, and some models that have been proposed to reflect these generalizations. A chart of some common handshapes is offered in Figure 10.1 for reference.

We begin by presenting parameters along which lexical contrasts are made, each of which will later be shown to constitute a subcategory of hand configuration features. After these preliminaries, the chapter proceeds to construct a model of hand configuration that is motivated by the clustering of features in classes, both in underlying representations and in phonological processes. The overall structure of the model relies on the theory of feature geometry (e.g., Clements 1985, Sagey 1986, Halle 1992).

We have seen how basic sentences are structured in ASL (Chapter 18) and LSB (Chapter 19). We turn now to the structures associated with additional sentence types. What these sentence types have in common is that they all may involve functional categories – those categories other than the lexical categories, N, V, A, P. Functional categories (such as Determiner, Agreement, Aspect, Negation, and Tense) may host lexical items (words or affixes) in their heads, but in some cases they are postulated to host only features. In either case, the presence of a functional category will often have an effect on some other part of the structure – for example, by requiring movement of some other element to its specifier. The element in the head of a functional category and the element in its specifier “agree” through “spec–head agreement.” This process is used in accounting for a number of phenomena. For example, we have already seen that the subject of a sentence may appear in [Spec, TP]. If the verb moves (through Agr) to T, then the subject and verb will check each other's features, so that subject–verb agreement is obtained.

It has been proposed that it is in functional categories where the differences between languages are coded (Borer 1983, Chomsky 1993, but see Snyder 2001 for support of the view that not all cross-linguistic parametric differences are associated with functional categories).

In this unit, we have explored a wide range of phenomena. We have discovered some facts, made some observations, and learned some things about the syntactic structure of sign languages. As in many areas, once we know a bit about something, we have a much greater understanding of what we don't know, and that is certainly the case here. Much more research is needed to make new and more refined generalizations about data, in the service of addressing theoretical questions.

This book focuses on the ways in which sign languages display the universal properties of all languages. Certainly when it comes to syntax, we have seen many similarities between what has been found for sign languages and what is known from the much longer study of spoken languages. But we have argued that studying sign languages contributes more to linguistic theory than studying any other exotic language. This is because where we find similarities across modalities, we can be more certain that we have discovered true universals. Even more important, where we find differences we can begin to understand the contribution of modality to language.

In this chapter we expand on the points just made. We summarize the findings from the chapters on syntax. We outline the need for further research. And we look at the unique position of sign languages for enhanced understanding of the relation between language and modality.

A striking difference in the transmission system of languages in the two modalities is the existence of two anatomically identical articulators in sign languages: the two hands. Spoken languages have no such potential. On the assumption that the human organism will make full use of its articulatory system, within the relevant modality, in the service of communication, one would expect that both hands would be used in sign language. And indeed they are. But do they function linguistically as two independent articulators in the words of sign language, resulting in a significant phonological difference between the two modalities? Researchers are in agreement that the answer to this question is “no.” The physiological existence of a second articulator generally does not mean that there are two completely independent articulators in the formation of words in the sign language lexicon. Rather, the non-dominant hand (h2) is always in some sense subordinate to other structural elements at the phonological level. This is the most important discovery about the non-dominant hand, as it offers novel insight into the relationship between phonetics, phonology, and the lexicon. What we see is a potential articulator with many degrees of freedom that behaves in a highly restricted way in the words of sign language lexicons.

If we were to approach sign language morphology from a simplistic and surface-oriented viewpoint, we would be confounded at once. Most of the word formation in sign languages does not consist of the linear affixation of concrete morphemes that bear a one-to-one correspondence with a meaning or grammatical function. Instead, the morphology of sign languages lends support from a different modality for the contemporary generative view of morphology – a morphological component that is word-based, and involves forms and processes that are often abstract and are not necessarily concatenative. Verbal bases may be associated to partially specified skeletal templates to form various verbal aspects; certain verbal forms may be reduplicated and their movements altered to derive nouns; classifier morphemes associate non-concatenatively to movements and locations to create complex forms that depict locative relations and different path shapes and manners of motion.

Classical morphological properties are also found in sign languages. There are sequential affixes that evolved diachronically from free words in the sign languages we have studied. Derivation, inflection, and compounding are all attested in many sign languages. This means that productive word-internal processes for forming new lexemes and for marking syntactic relations among words are robust in sign languages, as they are in most spoken languages – a significant discovery for defining the human language faculty. The sign language system supports allomorphy as well – more than a single form for the same word partial.

The existence of productive inflectional and derivational morphology in sign languages that have been studied indicates that lexicons of sign languages have much in common with those of spoken languages. Form–meaning correspondences must be listed together with part-of-speech and other syntactic properties. Word-formation rules must also be contained there, be they rules of simple affixation or of templatic association. Productive rules afford a language a way of expanding its lexicon, and this option is exploited in sign languages as it is in their spoken counterparts.

Two other ways in which sign language lexicons may expand are through the lexicalization of classifier constructions and through borrowing. Lexicalization and borrowing are commonly found in spoken languages as well, but in sign language, each has properties unique to the modality. Insofar as classifier constructions are often different from words in semantic, syntactic, phonological, and prosodic structure, their transformation to words is necessarily multifaceted, posing different challenges from those found in spoken language lexicalization. And as sign languages may sometimes reach over into the spoken modality to borrow, the borrowing process also has properties that are different from those that characterize borrowing from one spoken language to another. This chapter focuses on those processes, aiming to distill the general linguistic properties from the modality-rich solution in which they are immersed. Most of the chapter is devoted to the lexicalization of classifiers, presenting examples of monomorphemic signs that are obviously descended from polymorphemic classifier constructions.

At the very core of language is the word – the free-standing unit that unifies form and meaning. The word lists or lexicons of languages hold a vast number of words – an estimated 32,000 for adult speakers of English, for example. Many words are complex, consisting of more than one component that bears meaning and/or plays a grammatical role. The study of these complex word forms is the domain of morphology and the subject of this unit. In it, we will show that sign languages have a wide range of morphological processes, some fully productive, some idiosyncratic, all influenced by general linguistic organizing principles and most molded by modality-specific factors as well. In a sense that will become clear in the following sections, a lot of the “action” in sign language grammar takes place in the morphology.

Three observations suggest why sign language morphology may give us so much insight into the workings of the grammatical system. First, all natural sign languages have an iconic base. Indeed, it would be quite odd for a language in a manual–visual modality to avoid exploiting its ability to represent visual images and spatial relations iconically. Yet, despite the fact that they are often based on iconic images, the words of sign languages may be morphologically complex. In fact, the second noteworthy point is that there are many processes for making complex words in these languages. In some of these processes, the component parts of complex words are also relatively transparent.

The designation of location as a major phonological category in sign language is unquestioned. Clear evidence is presented in Chapter 8, where the ASL minimal pair ugly, summer, distinguished only by some feature of location, is illustrated in Figure 8.2b. Like hand configuration, the location category is made up of subcategories with different characteristics. In particular, the major body area (such as the head) remains constant within a morpheme, while different subareas (such as the forehead or the chin) may have two different specifications in that domain (Sandler 1989). This categorization, too, is widely accepted. There is, however, one area of controversy with respect to locations that may be stated in terms of the following two views: (1) locations are a sequential segment type (as consonants are in spoken language); or (2) locations are a category on a par with hand configuration in a single feature hierarchy (like the place features of a segment in a Feature Geometry model). In this chapter, we will demonstrate the category-internal organization about which there is a consensus. We adopt the Hand Tier framework to represent it, making certain changes from the original model. The more controversial issue and what is at stake in it are laid out in the conclusion to the chapter. As this issue is related to the notion of syllables in sign language, it will be taken up again in Chapter 14.