W1A-009 ASL syntax-0.txt
3 The Syntax of Space
3.1 Spatial Organization - Nominal Loci and Verb Directionality

In so far as the production and recognition of visual patterns is dependent on spatial distinctions, it is of course trivially true that spatial organization constitutes one dimension of sign language, just as it is true that speech can be described in acoustic terms. The description of sign in terms of its use of space can thus proceed on what we might term the 'phonetic' level. But it is also the case that the spatial dimension can lay claim to significance on the syntactic level of explanation also - as indeed on the level of discourse, though this will not be our primary concern here. In this chapter I will attempt to provide a framework within which the analysis of'spatial syntax' in HPSG terms might proceed. To begin with, I will look at the association of nominals with locations in signing space; following this I will explore the way in which certain verbs exploit this mechanism of'spatial indexing'.

Referring nominals in ASL are frequently associated with particular points, usually called loci, in signing space (Lillo-Martin and Klima 1990, Meier 1990, van Hoek 1992). The effect of this assignment of location is analogous to the assignment of abstract indices that is generally assumed in syntactic, and indeed discourse-oriented, accounts of reference and coreference: a locus is uniquely associated with the referent of the nominal, and this association may be exploited to refer anaphorically to the referent at any point in the succeeding discourse. In principle, there is no limit on the number of loci that may be established. A locus can be assigned to a referent in one of a number of ways (Lillo-Martin 1986). If the referent is an entity physically present, then that entity's actual location will, in general, function as its locus. An entity not present in the signing situation may acquire a locus through being signed in a particular, arbitrary position on its first appearance in the discourse, or it may be signed in neutral space and then explicitly assigned a locus through pointing. Alternatively, the signer may gaze at the locus while making the relevant sign.

Once established, a locus can be exploited referentially in a number of ways. Most obvious, perhaps, is the case of reported conversation; here, the signer commonly adopts the role of each of the participants in the reported conversation in turn. The role being played at a given moment is indicated by body orientation and gaze, and these parameters are determined by the loci assigned to the (absent) speaker and addressee. Loci are also exploited in a way that is apparently analogous to pronominal reference in spoken language: this is achieved by pointing to the appropriate locus with the index finger. Meier (1990) points out that while it is clear that ASL has gestures which, in certain contexts, are best rendered in spoken languages as personal pronouns, it does not follow necessarily that these are in fact pronouns in the same sense, since the use of pointing to indicate reference in discourse is nearly universal in human communication but is not generally considered to be a linguistic phenomenon. However, Meier goes on to adduce evidence in support of the view that the pointing employed in ASL is linguistic in nature; among his arguments are the fact that deictic point-gestures are interspersed with unambiguously linguistic signs, and the fact that similar syntactic constraints apply to their distribution as to that of other signs. Finally, spatial loci also play an important role in designating the participants in the relation introduced by certain kinds of verbs, and in specifying their role in the relation. In this chapter I will be concerned with capturing the pronominal and verbal uses of space in ASL.

3.1.1 The ASL Pronominal System and Referential Indexing

One argument mitigating against the claim that ASL pointing signs are pronominal is that, since there is in principle no limit to the number of loci that may be established in signing-space, there must also be no limit to the number of pronouns that must be present in the lexicon. If we accept this, then we must accept that there is indeed a substantial qualitative difference between the pronominal system of ASL and that of any spoken language, since there is no known spoken language that has an open-ended inventory of pronouns. Now, it is certainly true that, if we accept ASL points as pronouns, we must also accept that each entity in a given discourse may receive a uniquely assigned pronominal form. The English pronominal system must be considered sadly impoverished by comparison; any number of individual male referents in a discourse, for example, must be content to share a single he among themselves. GB theory and HPSG share a belief, however, that this degenerate paradigm is the surface manifestation of an underlying abstract, but psychologically real system of reference-tracking that involves abstract entities called indices. These, like spatial loci in ASL, are uniquely assigned to referents, and must hence be assumed to be infinite in number, since an infinite number of distinct referents may in principle be referred to in a given discourse. In HPSG, as we have seen, it is assumed that part of the informational composition of indices are the parameters alluded to above, namely, person, number and gender (for English, at least). For Pollard and Sag (1994), these features serve simply to help distinguish indices from one another: "Indices bear formal agreement features, in much the same way that pushpins employed by military strategists to represent army divisions might come in different colors to represent different countries. (p.72)" Hence, the fact that there is a limited variety of pronouns in spoken languages is a consequence of the limitations imposed by the taxonomy of pronominal forms; pronominal agreement systems are multidimensional, but the set of possible classifications along each descriptive axis is nonetheless discrete and finite. The visual modality of a sign language, on the other hand, permits an alternative system of formally marking distinctions among referents; instead of labelling indices with features corresponding to qualities inherent in the referents to which they are anchored, they can be associated with physical locations, arbitrarily assigned or actual. It happens to be a property of such a system that, like color-coding, it allows distinctions along a continuum; there is therefore potentially an infinitude of overt distinctions corresponding to the theoretical infinitude of indices. Also like colour-coding of course, the upper bound on the number of distinctions that can in practice be made is determined by the limits on the precision with which humans can distinguish between adjacent points on a continuum.

The important point here is that there is in principle no conflict between the facts of ASL and the understanding of reference assumed in GB or HPSG. Each of these theories does in fact posit unique indices for each referent in a given discourse; the formal features of spoken language merely fail to reflect this. It is a consequence of the modality of ASL (and other sign languages) that they have the means to reflect overtly the one-to-one nature of index-referent mapping.

We saw in the previous chapter how HPSG deals with indices in relation to nominals: they are treated as being inherent to particular lexical nominals. Thus, book is specified in the lexicon as introducing an index with the agreement features 3rd, singular, neuter. There are only as many pronouns in the HPSG lexicon as there are morphological distinctions between pronominal forms according to agreement features; 'doubling-up' of pronominal function in a single form is easily captured thanks to the partial nature of information supplied by lexical feature structures. Thus, English you is unspecified for number and gender; the former may be supplied by the morphology of a verb subcategorizing it as a subject, the latter by virtue of coindexation, hence unification, with a nominal introducing a gender-specific index. However, if we adopt this account of pronouns for ASL, then we will indeed have to posit an infinitude of lexical pronouns, each introducing a distinct index, each one specified for a different morphology - i.e., a different locus. Standard HPSG thus does not appear to provide a satisfactory account of the pronominal system of ASL.

3.1.2 Directional verbs and the HPSG account of verb agreement

A further difficulty is presented by the phenomenon of directional verbs. ASL verbs can be broadly divided into two classes: non-directional and directional. Directional verbs in turn come in two varieties, uni-directional and bi-directional. Directional verbs, as the designation suggests, typically involve a specific movement from one locus towards another. In the case of uni-directional verbs, this movement often originates at a particular (invariant) point on the signer's body and moves towards the locus assigned to the entity filling the patient role in the semantic relation described by the verb. Thus, TELL, for instance, begins with a handshape at the signer's chin and moves towards the appropriate object locus. Both the origin and the target of movement of bi-directional verbs are dictated by the roles they assign: the agent's locus is the starting point and, again, the patient's locus is the movement's end-point; GIVE is such a verb. Plain verbs are those whose form is not affected by role-allocation, such as UNDERSTAND. There is a consensus among researchers into ASL as to how these verbal phenomena are best treated: one aspect of the form of a directional verb in ASL - its movement - is dependent on its arguments; since there is a clear analogy between such a dependency and the verb agreement phenomena which are pervasive in spoken languages, it is considered appropriate to analyze them in the same terms. Thus, directional verbs are often referred to as inflecting and non-directional verbs as plain verbs.

In GB theory, verb agreement is a phenomenon arising out of movement to the verbal node of an autonomous, structurally represented segment (INFL, or AGR) comprising 'a bundle of features' (to use the standard locution)- or, possibly, movement of the verb to the node containing the agreement features. In either case, agreement is construed as a morphological mechanism that is located in the grammar, and agreement features exist independently of particular verbs. In HPSG, by contrast, the standard assumption is that verb agreement is best dealt with in the lexicon. Agreement features are not encoded directly on verbs, however; rather, it is assumed that agreement is a direct consequence of argument selection. Since the elements of a head's valence lists are synsem objects, it follows that verbs are capable of selecting the INDEX feature of their NP arguments. An English third-singular verb is thus one that selects a subject NP whose INDEX has the features [PERS 3rd] and [NUM sing]. The inflectional paradigm is captured by lexical rules specifying that particular phonological functions on the base form are constrained to accompany particular argument selections; hence, in English there is a 3rd-singular lexical rule that derives, from a verbal base form, a verb that has 3rd-singular morphology and the index of whose subject has 3-rd singular agreement features.

We have observed that, if we adhere to standard HPSG assumptions, we must posit the existence in the ASL lexicon of an infinitude of pronominal forms. Given the HPSG understanding of the nature of verb agreement, there is an even more acute problem in the case of verbs. Just as there is theoretically an infinity of pronominal forms, so we must assume that the inflectional paradigm for each directional verb is open-ended; and, given the foregoing assumptions, we must also assume that each form is lexically represented. Clearly, while the number of inflectional forms available for uni-directional verbs is equal to the number of available indices, the number of forms of bi-directional verbs approaches the square of this figure. Lexical rules cannot simplify matters here; since each distinct inflectional form requires a distinct lexical rule to derive it, the number of lexical rules needed will be equal to the number of verbal forms.
