Parámetros Fundamentales de la Arenisca “U”

The notion of lexical versus functional categories has been carried over into modem syntactic theory from traditional approaches to grammar, and whilst it retains some empirical and intuitive utility - for example in the description of psycholinguistic data and neurolinguistic deficits - it has remained relatively undefined in current syntactic theory. This presents a serious difficulty, especially when we consider the data obtained from investigations of agrammatic aphasia, because one of the defining characteristics of this disorder is standardly assumed to be a deficit affecting ‘function w ords’ (e.g. Alajouanine 1968, Tissot, Mounin & Lhermitte 1973, Caplan 1985, Howard 1985, Marshall 1986, Grodzinsky 1990 and many others). The underspecification of the distinction between lexical and functional categories is particularly pronounced in the case of prepositions, which apparently occupy an indeterminate position within this dichotomy, yet which are frequently used as experimental stimuli in investigations of

various acquired language deficits and cited as diagnostic evidence in descriptions of the same (e.g. Schwartz, Saffran & Marin 1980; Bemdt 1987; Grodzinsky 1988; Miceli, Silveri, Romani & Caramazza 1989; Biassou et al 1997- see below for some further discussion).

In common with many other cases of function word deficit, M C ’s difficulties extend to prepositions^. Although the inclusion of prepositions in the class of ‘functional categories’ employed by many researchers in aphasiology usually goes unquestioned, the assumption that prepositions are functional in nature is not unproblematic. Accounts of aphasie deficits which show that prepositional elements are included in the class o f items damaged in nonfluent aphasia^ have typically either ignored the problems or have attempted to explain the pattern of performance with (inadequate) recourse to notions from current syntactic theory.

Examples of the former approach, in particular, proliferate, and the paper mentioned above, by Biassou et al (1997), is a case in point. The stimuli presented to the patients in whom Biassou et al were trying to demonstrate a lexical / functional distinction were controlled for frequency, number of phonemes and syllable structure, to achieve a maximal matching between the ‘closed class’ and ‘open class’ test items; but, curiously, they did not control for word class - prepositions were included in the mixed bag o f ‘closed class items’. Consider also the following instances from the neuropsychology literature. Bemdt (1987) presents an overview of the characteristics of spontaneous speech in several different aphasie patients. The two she describes as ‘severe nonfluent’ are characterised as producing more nouns than pronouns, omitting determiners, not producing any prepositions, and omitting verbal inflections and auxiliaries - suggesting that preposition omission is as characteristic of nonfluent aphasie

^ Though it should be noted that the errors made by aphasie patients on various word classes are frequently not documented in sufficient detail to make independent analysis of these errors possible. Aphasie errors on prepositions tend to be subsumed under the relatively undefined notion of ‘function word errors’. For example, see Berndt 1987, Biassou et al 1997, and others.

^ The term ‘nonfluent aphasia’ is a syndrome classification which is often used interchangeably with the term ‘Broca’s aphasia’. It refers to the observation that aphasie patients with syntactic deficits frequently have a ‘telegraphic’ speaking style, which is slow and effortful and characterised by the omission o f many function words. It contrasts with ‘fluent aphasia’, which is more often associated with Wernicke’s-type aphasies, or jargon aphasies: those with few syntactic difficulties but greater problems with substantives. See Goodglass (1983).

language production as the omission of inflectional morphology, but not at any point pausing to consider why this should be so, given the ambiguous nature of prepositional elements. Schwartz, Saffran and Marin (1980) used reversible locative sentences (such as The square is under the circle) in a comprehension task for agrammatic aphasies; the use of sentences which contained prepositional phrases was actually introduced to control for possible pragmatic biases on their reversible sentences which did not contain locatives. No reference is made to the fact that prepositions themselves may introduce new and more relevant (because syntactic) variables; in fact, although the patients tested did perform much worse on the prepositional items than on comparable items which used verbs, there is no mention at all of the lexical status of V and the (possible) functional status of P. Miceli, Silveri, Romani & Caramazza (1989) document the omission and substitution errors of a large group of agrammatic aphasie patients on functional categories in spontaneous speech; prepositions are reported as absent or substituted at least as often as other categories such as articles, clitics and auxiliaries, but no comment as to their ambiguously lexical / functional status is made. In their protocol for the analysis of agrammatic production, Saffran, Bem dt and Schwartz (1989) instruct that the number of closed class words in a sample be calculated (rather than counted) by subtracting the number of substantives (which does not include prepositions) from the total number of words in the sample - so the kind of closed class words present in a speech sample are never analysed, despite the obvious relevance of such analysis for agrammatic aphasia. And there are many other, similar, examples of studies which purport to examine functional categories or closed class words, but which in fact gloss over any such analysis.

In the face, then, of strong empirical evidence that prepositions pattern with other functional elements in aphasia, coupled with the lack of a fully articulated account of the syntactic nature of prepositions, and a general (if unformulated) acceptance that the underlying deficit in nonfluent aphasia is somehow syntactically defined, it seems clear that some recourse to syntactic theory is required to advance the search for an explanatory account of such deficits. Nevertheless, attempts to provide a syntactic explanation for the preposition deficit in nonfluent aphasia are still rare and have not on the whole been particularly successful.

affecting certain prepositions in agrammatism by invoking the notion of government, and suggesting that only governed prepositions, such as those in lexical passives ( ‘John is interested in M ary’) or those which are subcategorised by V ( ‘John is counting on M ary’) are damaged; ungovemed prepositions (such as by in a syntactic passive, analysed by Grodzinsky as adjoined to the S node) are spared. Grodzinsky claims to find results which support his hypothesis; however, other researchers have found differing patterns of performance (e.g. Tesak and Hummer (1994) found that there was no govemed/ungovemed distinction made as regards prepositions in the spoken output of Broca’s aphasies); and Grodzinsky’s account is in any case conceptually undesirable, since it requires the existence of a selective deficit of government pertaining to only one category - P - which is a separate deficit from that assumed to have an effect on the other damaged categories in the syntactic representations of the agrammatic subjects'^. I return briefly to this issue below (see end of section 4.6).

A somewhat similar attempt to capture the complexity of defining the class of prepositions, and how they should be treated given understanding of the mechanisms thought to underpin various acquired language disorders, was undertaken by Friederici and colleagues in the 1980s. Friederici (1981) and Friederici, Schonle and Garrett (1982) presented data from groups of Broca’s and Wernicke’s aphasies which suggest that Broca’s aphasies omit prepositions in comprehension and production tasks, whereas W ernicke’s aphasies make within-class substitution errors. This contrast was proposed to arise from Broca’s aphasies’ inability to identify the syntactic category to which prepositions belong, since they have a particular deficit in the processing of ‘a specific fixed (closed) class of items’ (Friederici 1981:198); W ernicke’s aphasies can make use o f such syntactic information and have more semantically-constrained difficulties in identifying one particular preposition, resulting in within-category substitution errors. There is no comment in these studies concerning the anomalous assumption that prepositions are a straightforward exemplar of such closed-class items, but Friederici’s

^ The proposed nature o f the main deficit is not specified by Grodzinsky in this particular paper, but one would assume that it is related to his famous trace deletion hypothesis (laid out most explicitly in Grodzinsky 1990) - clearly not a proposal with any explanatory power as far as the preposition problem is concerned, since there are generally no traces to be deleted from the syntactic representation of prepositions (though there may be movement of the complement of P - e.g. Kayne 1994); hence the need to propose a second, entirely separate, deficit to capture the fact that prepositions appear to pattern with other, damaged, functional categories in agrammatic aphasia.

(1982) comparison of the performance of Broca’s and W ernicke’s aphasies on grammaticality judgement and production tasks involving prepositions does address this issue. Friederici discusses the possibility that prepositions may not be straightforwardly closed class, but that they may have varying degrees of semanticity as well. Using German, she drew a distinction between lexical prepositions, which have semantic content related to spatial and temporal properties; and obligatory (syntactic) prepositions, which are those selected for by particular verbs. These different kinds of preposition may be realised in identical orthographic and phonological forms, as in the examples given in (1) below (Friederici’s 1 and 2):

( 1 ) a. Peter steht a u f dem Stuhl. Peter stands on the chair, b. Peter hofft aw/den Sommer.

Peter hopes for the summer.

Friederici found that Broca’s aphasies had more difficulty in interpreting and producing those prepositions which have a purely syntactic role, as in (1) b, compared to those with more semantic content, as in (1) a. (Wernicke’s aphasies seemed to show the opposite pattern, having greater difficulty with ‘lexical’ prepositions than with syntactic or ‘obligatory’ ones, and making substitution errors within syntactic categories.) This led Friederici to propose that the widely-held belief that Broca’s aphasia can be (partly) characterised in terms of the non-availability of closed-class vocabulary items may be too simplistic; she proposed that a more applicable distinction may be in terms o f the ‘functionality’ of vocabulary items - that is, whether they are predominantly semantic in nature, in which case they will be more readily accessible to Broca’s aphasies, or predominantly syntactic, in which case Broca’s aphasies will have more difficulty. To elaborate, Friederici (1985) places evidence from normals and Broca’s aphasies within a model of speech production put forward by Garrett (1982, discussed more in chapter 6, section 6.2.1 below) to argue that lexical prepositions (those with semantic content) are involved in processes at levels of representation dealing with both meaning and structure, whereas obligatory prepositions are processed only at the structural (or ‘positional’) level. In Broca’s aphasia, the structural level is disrupted (again, compare

this to Druks and Freud’s account of M C ’s deficit, discussed in chapter 6, section 6.2.1). Unfortunately for Friederici’s proposal, it seems that Broca’s-type aphasies do not necessarily show effects of the semanticity of prepositions. For instance. Mack (1981) found no support for the hypothesis that non-fluent aphasies have more difficulty in interpreting commands involving locative prepositions because of the syntactic demands of such items - rather, he found an effect of task complexity, which Friederici herself has admitted seems to be an issue. Similarly, M C ’s performance on prepositional elements cannot be captured in such a way, since he is equally poor at reading all prepositions and shows no effects of a semanticity gradient in prepositions (or any other category for which his reading is impaired).

A major criticism of neuropsychological approaches to function word deficits in aphasia is that the notion of ‘function word’ or ‘functional category’ is not defined; similar problems are encountered in linguistic theory. The next section considers various attempts to clarify the nature of the split between lexical and functional categories.