Andrew Radford - Linguistics An Introduction [Second Edition]

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Agrammatism

Recall from the section 15 (p. 214) that according to the classical clinical description of aphasias, the sentences Broca ’s aphasics produce in spontaneous speech are characterised by their simplicity or reduced syntactic complexity. These sentences are often incomplete, with functional elements (including grammatical inflections) being omitted. These problems also usually occur in writing, whereas sentence comprehension is said to be more or less unaffected.

Consider (489), where we see examples of Broca’s aphasics’ attempts to produce some simple English sentences, for illustration:

(489)

Reconstruction of target

Realisation

a.

He’s going on the bus

He going bus

b.

When did this happen?

This happened?

c.

The woman is packing the case

Woman is packing the case

d.

I only passed my test in the afternoon

Only passed my test afternoon

e.

They are pulling it

Pulling it

As is shown by the reconstructions of the targets in (489), we can paraphrase the deviant or simplified utterances produced by Broca’s aphasics by normal English sentences which differ only minimally from the actual realisations. In all cases, the realisations are syntactically less complex than the target reconstructions, and omissions and simplifications typically affect functional projections (DP, TP and CP). For example, in (489a), the head T position of TP is left empty instead of being filled by the auxiliary is, and the determiner the is omitted from the head D

position of the target DP the bus (in addition, the preposition on is omitted from the target PP on the bus). Similarly, in (489b), the wh-operator when is omitted from spec-CP, and the preposed auxiliary did is omitted from C. In (489c) and

(489d), the determiner the is omitted from the head D position of the target DPs the woman and the afternoon, and in the latter, the pronominal D I in spec-TP is missing (and the preposition in is omitted from the target PP in the afternoon).

And finally, in (489e), the auxiliary are is omitted from the head T position of the target TP They are pulling it, along with the D-pronoun they in spec-TP.

According to the clinical definition, agrammatism in Broca’s aphasics is

modality-specific. That is, agrammatic errors are believed to occur in one modality only, namely in language production, with sentence comprehension unim-

paired. If this were correct, then agrammatism would be a disorder of some

peripheral language-production mechanism, with the central cognitive system

underlying the knowledge of grammar still being intact. Research in linguistic aphasiology, however, provides us with a somewhat different picture. It has been shown, for example, that Broca’s aphasics have problems in comprehending

functional categories as well as in producing them. Such findings suggest that the agrammatic deficit involves impairment of the underlying linguistic system as well, and not just a disturbance in one modality.

Syntactic disorders

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Sentence comprehension in Broca’s aphasics can be studied only through

structured experiments. Aphasiologists have recently begun to adopt different psycholinguistic techniques, e.g. linguistic judgement tasks, lexical decision experiments and reaction-time techniques in order to assess agrammatics’ knowledge of grammar. Let’s look in some detail at one experiment which investigated a single, well-defined syntactic phenomenon, namely the fact that sentences like (490a, b), differing only in the positioning of the definite article the, have quite distinct interpretations:

(490) a.

The man showed her baby the pictures

b.

The man showed her the baby pictures

In (490a), the DP her baby functions as what is sometimes known as the ‘recipient’

complement of the verb (it refers to the individual who receives something – in this case, visual stimulation – in the action referred to by the verb) and the DP the pictures is the ‘theme’ complement, referring to whatever is generally affected in the action referred to by the verb (see section 23). By contrast, in (490b), her is the ‘recipient’ complement and the baby pictures is the ‘theme’ complement. The crucial factor underlying this distinction is the determiner the. Since in (490a)

the appears between baby and pictures, we cannot analyse these two nouns as

parts of a noun compound in this structure. (Note that noun compounds don’t

allow determiners between the two nouns: we have such compounds as loft space and armchair, but not *loft-the-space and *arm-the-chair.) In (490b), however, the compound-based interpretation is possible, due to the absence of the between baby and pictures.

Returning now to agrammatism, in the study we are concerned with, the

contrast between (490a) and (490b) was exploited to conduct an interesting experiment on sentence comprehension in agrammatic patients. It was argued

that if sentence comprehension was unimpaired in agrammatic aphasics and

patients were relying on syntactic clues to process sentences – such as the

presence and position of a determiner – then sentences like (490a, b) should be correctly interpreted by these patients, just as they are by normal adult speakers of English. If, however, the agrammatic deficit also affects comprehension, and if agrammatics ignore the function word the in comprehension in the same way as they omit it in production, as in (489c), then (490a, b) should be ambiguous for them in the same way as (491) is for normal adults:

(491)

The man showed her baby pictures

A moment’s reflection should reveal that either her or her baby can be interpreted as the recipient, with the theme being correspondingly either baby pictures or pictures.

To test this prediction, a sentence–picture matching task was used in which

subjects had to choose from four alternative pictures that were presented for each sentence. Suppose the presented sentence was (490a). Then one picture (the correct one) illustrated a man showing pictures to a woman’s baby, while a second

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(incorrect) contained a man showing pictures of a baby to a woman. Two further pictures (both incorrect) were included to test for lexical comprehension, examples being appropriate pictures for the sentences in (492): (492) a.

The man showed her girls the hats

b.

The man showed her the girls’ hats

The results of this experiment demonstrated that agrammatics made few lexical errors, i.e. they hardly ever chose pictures appropriate to (492a, b) when the presented sentence was (490a), but in nearly half of the trials, they picked the picture portraying the nominal-compound reading, i.e. the picture appropriate for

(490b). In other words, the agrammatic patients appeared to treat (490a) and (490b)

as ambiguous, an interpretation which is consistent with them failing to process the definite article the and thus treating both sentences as if they were (491). Given that the comprehension disorder found in this experiment is parallel to the syntactic errors that occur in agrammatic production, in that both involve errors with function words, we may conclude that agrammatism is a fundamental disorder of the

linguistic representational system (i.e. the grammar), rather than a peripheral impairment to one specific modality only.

But how can we characterise agrammatism? The most widely known syntactic

theory of agrammatism is Yosef Grodzinsky’s hypothesis of an impairment to the internal feature specification of functional projections. This theory is controversial, but it provides a very clear and explicit account. Recall from section 15 (p. 215) that in languages such as Hebrew and Italian, in which many inflections cannot be dropped without violating word-structure properties, agrammatics produce many inflectional errors, e.g. gender errors, number errors, etc. A typical example of such an inflectional error from an Italian agrammatic patient appears in (493):