FUNCIONAMIENTO Y APLICABILIDAD DE LA ACCIÓN FISCAL

An elicitation task was used which was slightly modified from that used in Chapters 4 and 7. In that task the child was primed with both the stem and past tense form in an effort to improve on the low scores that the G-SLI children achieved in van der Lely and Ullman’s (2001) task. From the results of the task used in Chapters 4 and 7 ,1 felt confident that the children would achieve scores higher than in van der Lely and Ullman’s task without the need for the past tense to be presented. I also dispensed with the toy animals used to introduce the task in Chapters 4 and 7, judging that the youngest typically developing children would be able to manage the task without them, while the older G-SLI children would consider the toys, and therefore the task, too ‘babyish’.

The lead in was of the form ‘Everyday I get a present. Yesterday I a present. There were 2 practice sentences, using irregular go and have, neither of whose

past tense corresponds to the phonological characteristics of the irregular experimental stimuli. One randomised, set order was created for all participants, and is presented in Appendix D.2.

8.2.3. Participants

In this experiment, and in those reported in Chapter 9, I use a different method for selecting control groups. In the experiment reported in Chapter 6 I used individual

matches. While this has the advantage of ensuring that each child in the G-SLI group is matched on exact or near-exact raw scores of grammar and vocabulary measures, the disadvantage is that one cannot see any pattern of development within the control children unless one afterwards assigns them to groups based on age (the method I use in the studies reported in Chapters 4, 5, 7, 10 and 11). For this experiment and those described in Chapter 9, I use three control groups, each encompassing approximately a twelve­ month age band. 36 control children are divided into 3 groups of 12 each.

• LA1 controls - aged 5;04-6;06 (mean age 6;00) • LA2 controls - aged 6;07-7;06 (mean age 7;01) • LA3 controls - aged 7;09-8;05 (mean age 8,02)

As was the case for the control groups in previous chapters, two receptive language tests were administered - the TROG and the BPVS. Scores for all participant groups are presented in Table 8.2.

Table 8.2. Participant details

Measure G-SLI N = 13 LA1 controls N = 12 LA2 controls N = 12 LAS controls N = 12 Age Mean 13;05 6;00 7;01 8;02 Range 9;08 - 17;09 5;04 - 6;06 6;07-7;06 7;09 - 8;05

TROG Raw, mean 12.62 14.53 16.17 17.17

Raw, range 6 - 1 7 1 2 - 1 7 1 4 -1 9 1 5-19

z-score, mean -1.76 0.59 0.59 0.47

BPVS Raw, mean 77.23 68.80 76.92 91.00

Raw, range 4 7 - 1 0 7 60-81 6 3 - 9 7 71-106

z-score, mean -1.80 0.55 0.35 0.49

In order to determine how the G-SLI group compares with each of the control groups on each of the language measures, a series of independent samples t-tests was carried out. For the TROG, the G-SLI group did not differ from the LA1 controls, t (23) = - 1.876, p = 0.073, but it scored significantly worse than the LA2 group, t (23) = -3.335, p = 0.003, and the LA3 group, t (23) = -4.750, p < 0.001. Even though the G-SLI and LA1 groups are not well-matched, the LA1 group is the closest control group to the G-SLI group in terms of grammatical ability. For the BPVS, the G-SLI group did not score significantly differently to the LA1 group, t (23) = 1.722, p = 0.105, or the LA2 group, t (23) = 0.057, p = 0.995, but did score worse than the LA3 group, t (23) = -13.7692, p = 0.033. Therefore the

LA2 group is the best-matched control group for vocabulary. These matches are indicated in red in Table 8.2. The LA3 group has significantly higher grammatical and vocabulary abilities than the G-SLI group, and is included in order to determine the pattern of typical development.

8.2.4. Predictions

Predictions for both regular and irregular verbs rely on the hypothesis that stems ending in

-d/t are less likely to be suffixed than those ending in W . For regular verbs, I predict that

the G-SLI and control groups will both achieve lower rates of inflection with d/t-id verbs compared to W -D verbs. No studies have previously compared one- and two-syllable verbs. The SS-D verbs chosen for this study have trochaic foot structure and end in a vowel, so they are not any more prosodically complex than monosyllabic W -D verbs. I therefore predict that performance will be equivalent on W -D and SS-D verbs for both groups, with d/t-id verbs harder than both.

For irregular verbs, interest centres on two types of errors: over-regularisations (e.g. throw —> *throwed) and bare stem responses (e.g. meet —> *meet). For the G-SLI group, I predict lower rates of over-regularisation for d/t-id and VC-D verbs compared to W -D verbs. Because the factors that reduce the likelihood of over-regularisation are the same that promote bare stem responses, I predict more bare stem responses for d/t-id and VC-D verbs than for W -D verbs. I make no predictions as to whether this group’s performance will be lower for d/t-id or VC-D verbs. For typically developing children, I have shown that prosodic complexity does not affect regular inflection (see Chapter 7), and so I predict no distinction between W -D and VC-D verbs for either over-regularisation or bare stem responses, but I predict fewer regularisations and more bare stem responses for d/t-

id verbs compared to both W -D and VC-D verbs.