LAS REFORMAS CONSTITUCIONES, PARA EL FORTALECIMIENTO DEL TRIBUNAL CONSTITUCIONAL MEXICANO

Children in both the G-SLI and LA1 groups both exhibit phonological pressure to reduce the output to the size of a trochaic foot, but which syllable is actually deleted is determined by how much pressure there is to retain the suffix - presumably for the G-SLI group the pressure is to keep the suffix, perhaps because of its semantic content. The LA1 group, on the other hand, is not under pressure to keep the suffix.

Do data from the non-word repetition test discussed in Chapter 5 shed light on which weak syllable of sww words G-SLI children are more likely to omit? Remember that weak syllable deletion is rare in these children. In fact, of the three children who show the greatest maximal word effects, QC and GS delete 0 out of 32 weak syllables in sww non­ words, and OD deletes 5 out of 32. OD’s omissions seem to be of the final syllable, e.g.

fakletala -> sakleta, but this is not conclusive, because it is impossible to know whether the

retained schwa is from final weak syllable or not, and whether It! is retained over III for sonority reasons (see Section 10.1.3). In the derivational task OD retains the suffix, i.e. the last syllable, and deletes the middle syllable - he never omits the suffix. The fact that the control children show a different pattern of syllable deletion on that task - they delete the suffix - suggests that the choice of which syllable is to be deleted is down to morphological factors.

When G-SLI children truncate the stem in order to accommodate the derivational suffix within the minimum word, are they doing something outside the bounds of Universal Grammar, or does this phenomenon exist in adult language as well? A number of languages seem to impose conditions on maximal size of the word, but the phenomenon is little-researched. However, there is at least one example of stem-truncation in order to fit the suffix into an output that is limited in size by maximal word constraints. Yip (1992) discusses data from Anxiang, a dialect of Chinese. In Anxiang, diminutives are formed by

reduplication and suffixation of h r! on the reduplicated syllable. The maximal word constraint in Anxiang is even more severe than that of English: it limits the size of the maximal word to a syllable. Replacing the rhyme of the reduplicated syllable by h r! leaves only the onset of the original word, and if the word has a high vowel this forms a glide in the onset, e.g. Im ja n l —> Im jan m ja rl (lace’).

The finding that -er is omitted more frequently by the LA1 controls than by the G- SLI group raises problems for any account of SLI that proposes difficulties in processing non-salient material (e.g. Leonard, 1989). I invoked a phonetic saliency account for why the LA1 children omitted -er more frequently than -est (see Section 10.4). However, if G- SLI children have difficulty processing non-salient suffixes, then why don’t they omit -eft I argue that they don’t omit it because they recognise its semantic importance. If this account is on the right lines, we can make an interesting comparison with the study of regular past tense inflection in Chapter 8. In that study, G-SLI children omitted lid l at the rate of 43.27%, and yet lid l has more phonetic material than /a/, and is therefore more salient. The striking difference in omission rates between hd! and h i can be accounted for by the syntactic need for checking of tense features, an operation that is impaired in G-SLI grammar. An account such as the Surface Hypothesis, whereby SLI children omit suffixes of low phonetic salience, cannot account for their different behaviour with respect to lidl and Id.

However, I also accounted for some of the omission of tense inflection being a result of an impaired suffixation rule. The findings in this chapter are problematic for the CGC hypothesis in this very respect. If we conceive of a morphological rule as taking a stem and adding a suffix to it, i.e. the operation stem + suffix, then surely a deficit in this rule should affect past tense and comparative/superlative formation alike. I argued for the existence of morphological rules, and their impairment in G-SLI, in Chapters 3 and 4, and yet from the findings reported in this chapter it appears that there is no rule impairment - -

erf-est are not omitted. We expected to find lower rates of derivational suffix omission than

past tense suffix omission because syntactic feature checking does not play a part in derivation, but the finding that derivational suffix omission is almost nil challenges the Words and Rules (WR) model (Pinker, 1999; Pinker & Ullman, 2002). If rule use is defective in inflection, then why is it not defective in derivation? The WR model predicts that (productive) derivation should be impacted as well (Pinker, personal communication, January 2004). The contrast between the deficit in inflectional suffixation and the lack of deficit in derivational suffixation strongly suggests that the WR model needs to be refined.

- at the very least a distinction must be made between an inflectional rule and a derivational rule. Recall the effects of metrical complexity on the use of -ing and plural -s in Chapter 9. I argued that -ing, and perhaps -s, are not impaired per se, yet when the linguistic system is stressed through the addition of metrical complexity, those suffixes are prone to omission. The work presented in this chapter indicates that in the presence of metrical complexity inflection and derivation behave in different ways - inflectional suffixes are omitted and derivational suffixes are retained. This provides evidence for a cognitive distinction between the two.

Chapter 11. Further exploring derivational morphology - adjective