Estragos Jurídicos, Sociales, y Económicos 60

The Test of Phonological Structure (TOPhS, van der Lely & Harris, 1999) tests the effects of prosodic complexity on non-word repetition performance. Stimuli are varied according to the number of marked syllabic and metrical structures they contain (see Section 1.2.3.2 for a discussion of markedness). Three of the marked structures relate to syllable structure and two to metrical structure. The three syllabic structures are set out in Table 5.1, together with real words and examples drawn from the non-word stimulus set. In each of the examples, the segment string illustrating the relevant structure is underlined. Marked and unmarked syllabic structures are compared only in the stressed syllable.

Table 5.1. Syllabic structures varied in the TOPhS

Syllabic structure Real word Non-word

Onset no cluster unmarked gawn keta

cluster marked grawn kUta

Rhyme open unmarked dty keta

closed marked filter kesta

Word end V-final unmarked dty keta

C-final marked sit ket

As to metrical structure, the TOPhS is designed to vary the location of the stress foot relative to word edges. In the unmarked case, the edge of a foot is aligned with the edge of the word. Words consisting of a single foot have perfect alignment at both edges (as in dty, tea, sit). In polysyllabic words, misalignment is possible, resulting in marked stress patterns. Two of these feature in the non-word stimulus set, both involving the adjunction of an unstressed syllable at a word’s edge. In one pattern, an unfooted syllable is adjoined at the beginning of a word, as in bafnana}, defnial} (feet parenthesised). The other involves right-edge adjunction, where an unfooted syllable separates the end of a foot from the end of a word, resulting in antepenultimate stress, as in {Jennifer; {fantajsy. The structures are summarised and exemplified in Table 5.2.

Table 5.2. Metrical structures varied in the TOPhS

Metrical structure Real word Non-word

Left adjunction unmarked {dty} {keta}

marked bafnana} _fafketa}

Right adjunction unmarked {dty} {keta}

marked {Cana}da _{ketajla

In certain respects, string-based and prosody-based measures of complexity converge. For example, the extra segment that renders play longer than pay also contributes to the complexity of the onset in play. In other respects, however, the two types of measure produce quite different results. For example, on a phoneme or syllable count,

tidy and today are of equal complexity. However, in terms of metrical structure, today is

more complex than tidy by virtue of containing a left-adjoined syllable.

The TOPhS requires the child to repeat non-words that are systematically varied with respect to the five marked structures described above. The stimuli were constructed around four exemplars of CVCV structure which are manipulated to contain 24 different permutations of marked and unmarked structures, yielding a total of 96 stimuli. Each set contains stimuli ranging from a maximally simplex form, displaying only unmarked structures (e.g. keta), through progressively more complex forms, containing various permutations of marked structures (e.g.fakestala). Table 5.3 provides illustrative examples of non-words based on the CVCV form depa, where, ‘u’ and ‘m’ indicate unmarked and marked structures respectively. All non-words conform to the phonotactic constraints of English and are intended to be applicable to all dialects of English. In this way, the TOPhS allows us to test the prediction that non-words with marked structures will be repeated less accurately than those with unmarked structures.

Table 5.3. Examples of non-words based on the CVCV form depa

non-word onset rhyme word-end left

adjunction right adjunction depa u u u u u drepa m u u u u dempa u m u u u dep u u m u u badepa u u u m u depari u u u u m badrepa m u u m u dempari u m u u m badrempari m m u m m 5.1. Method 5.2.1. Procedure

Testing was carried out in a quiet room in the children’s school. The children were told that they were going to hear some made-up words that they would not have heard before and that they should repeat these words into the microphone. They listened to the digitally recorded non-words through high quality headphones and their repetitions were recorded onto a DAT tape. Four practice items were provided at the start of the task, and the 96 non-words were then presented in a set randomised order, at three second intervals. The time taken to complete the task was approximately 6 minutes.

The participants’ repetitions were transcribed online in broad phonetic IPA transcription and then subsequently verified against the recording. For the purposes of the statistical analyses responses were scored as either correct or incorrect. Voicing errors, e.g. Ipl for Ibl were not scored as incorrect, and neither was replacement of Irl by Iwl.

5.2.2. Participants

10 G-SLI children were administered the TOPhS. In addition, 20 children with typically developing language acted as controls. 10 children were individually matched to the G-SLI participants on exact raw score on the Test for Reception of Grammar (TROG; Bishop, 1983) (with the exception of one G-SLI child, GS, whose grammar control’s score is 3

points above). 10 children were individually matched on raw score (±3) on the British Picture Vocabulary Scales (BPVS; Dunn et al., 1997). In order to get a picture of typical development, those 20 children were then divided into two groups according to age. Details of the participant groups are shown in Table 5.4.

Table 5.4. Participant details

Measure G-SLI N = 10 LA1 controls N = 10 LA2 controls N = 10 Age Mean 12;00 5;09 8;09 Range 9;04 - 16;08 4;05-7;04 7;05-9;10

TROG Raw, mean 13 10.6 16.4

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

z-score, mean -1.60 -0.20 0.31

BPVS Raw, mean 76.5 58.9 89.6

Raw, range 4 7 - 1 0 4 3 3 - 8 0 6 9 - 1 0 2

z-score, mean -1.67 0.13 0.21

T-tests reveal that the G-SLI group does not score significantly differently to either the LA1 or LA2 group on the TROG, t (9) = 1.933, p = 0.085, and t (9) = -2.037, p = 0.072 respectively. The LA1 group is hence the better match in terms of grammar ability. The G- SLI group scores significantly better than the LA1 group on the BPVS, t (9) = 2.258, p = 0.050, but not significantly differently to the LA2 group, t (9) = -1.737, p = 0.116. The LA2 group is therefore the better match in terms of vocabulary ability.

5.3. Results