ELEMENTOS PARA ESTABLECER LA RESPONSABILIDAD POR ACCIÓN FISCAL

Figure 6.1 illustrates the relationship between regular morphology and two dimensions of verb-end phonology - phonotactic legality and prosodic complexity. As the figure shows, these dimensions are not orthogonal. Within the set of verbs that take regular past tense morphology, some, represented by the light grey shading, have inflected endings that are phonotactically legal (i.e. the same endings are found in monomorphemic words) and prosodically simplex (i.e. they do not contain a cluster). Examples of such verbs are played and sewed. Some regular verbs have prosodically complex endings, and they further divide into two groups depending on the phonotactic legality of that ending. Some have a cluster that is legal (dark grey shading), and examples include yelled and tossed. The remainder have a cluster that is illegal (black shading), with examples including hugged and danced.

Figure 6.1. Prosodic complexity and phonotactic legality in regular past tense verbs

This investigation considers not only the prosodic complexity of the inflected verb end, i.e. whether or not the verb ends in a cluster, but also the length of the preceding nucleus. For an inflected verb whose only verb-end consonant is the suffix, the preceding nucleus must be long because of a constraint in English on the minimal size of monosyllabic words - a verb (in common with other content words) has to be minimally a foot, which means that if it ends in a vowel, then that that vowel has to be long (see Section 1.2.3.1). This constraint on the length of the nucleus is not present if the verb stem ends in a consonant. In that case, the nucleus can be either short or long.

6.1.3. G ram m aticality judgem ent tasks

The task is a forced-choice grammaticality judgement task. Judgement tasks are widely used in psycholinguistics to inform us about children’s grammatical knowledge (McDaniel & Smith Cairns, 1996). They have been used to test knowledge of such syntactic aspects as binding theory, WH-movement, relative clause constructions and subject-auxiliary inversion (see references in McDaniel & Smith Cairns, 1996), as well as morphology (e.g. Montgomery & Leonard, 1998; Rice, Wexler & Redmond, 1999). Two types of task are used - open-ended and forced choice. In an open-ended task, the experimenter presents a sentence, e.g. * Whose did you read book, and the child says whether or not it sounds right. One disadvantage of open-ended tasks is that children have a bias to say ‘yes’ in their responses, which means they may accept an ungrammatical answer as correct even though they know that it is ungrammatical. This yes bias may reflect a social bias towards acceptance (McDaniel & Smith Cairns, 1996). In a forced-choice task the child has to choose which of two sentences is the right one, e.g. Whose book did you read/ * Whose

did you read book. A disadvantage of forced choice tasks is that children have to choose

just one of the two sentences, when in fact both might be acceptable to them.

If SLI children have a deficit in linguistic competence (i.e. in their actual knowledge of language), then their pattern of behaviour on a past tense task should be similar regardless of whether a judgement or production task is used (although the type of task may affect actual performance levels). On the other hand, if SLI is caused by a limited processing capacity (e.g. Bishop, 1994), then these children’s underlying grammatical representations are intact, and the differing task demands might give rise to different results depending on how much they stress the system. Bishop claims that ‘SLI children do have the underlying competence in that they understand the grammatical function of morphological markers, but fail to apply their knowledge consistently because of limitations on their processing capacity.’ (Bishop, 1994:508). This suggests that children with SLI should not be impaired for tense when tested on judgement tasks.

Few judgement tasks have been conducted to test SLI children’s morphosyntactic abilities, in contrast to the large number of elicitation tasks. Those that have been carried out with past tense stimuli have indicated that SLI children have difficulties with judgement, although it is not clear that they perform worse than their language-matched peers. In a longitudinal study of SLI children aged between 6;00 and 8;00, Rice et al. (1999) found that they only performed worse than language-matched controls at some time periods, and that they otherwise performed at the same levels. Montgomery and Leonard (1998) found that SLI children aged 8;06 performed significantly worse than age-matched controls but not MLU-matched controls. Van der Lely and Ullman (1996) showed that children with G- SLI judge stem forms like * walk and overregularisations such as * failed to be acceptable in past tense contexts. Taken together, these results indicate that SLI children’s difficulties with past tense formation are not confined to production, contra Bishop (1994).

As far as I am aware, the task reported in this chapter is the first to consider the impact of verb-end complexity on past tense judgements. A representation of prosodic complexity is essential when judging whether or not a regular verb is inflected. The tense change in roll -> rolled is signalled by the formation of a cluster at the verb end. Children who have difficulty representing clusters are predicted to have more difficulty judging rolled as the past tense form when compared to children who have no difficulty with clusters. However, it is not predicted that such difficulties in representation will lead to less accurate judgement of irregular past tense forms. Although the tense change in sell —> sold does involve the formation of a cluster, the tense change is also signalled by the change in

vowel quality. The child should be able to judge the tense of the verb solely by using the vowel cue, regardless of the accuracy of the verb-end representation.

6.2. Method