To find the within-language phonological predictors of NS reading, multiple regression analyses were conducted with the NS reading measures as dependent variables and NS elision, NS phoneme isolation, NS NWR and NS RON as predictor variables in the regression model. Firstly, a multiple regression analysis was performed on a collapsed data set. Secondly, analyses were also conducted for each group to find NS predictors of reading in the two instructional groups. The constant values, betas, standard errors and standardised betas for within language phonological predictors of NS reading are provided in Table 5.7 below.
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Table 5.7 Summary of within language hierarchical multiple regression with NS reading as dependent variable
NS word reading NS fluent reading
B SE B Β B SE B Β Step 1 Constant 10.13 9.2 -7.02 5.94 NS elision .91 .15 .59* .53 .10 .54* NS isolation .07 .15 .05 .10 .10 .10 Step 2 Constant -3.1 10.7 7.21 7.11 NS elision .80 .15 .52* .53 .10 .54* NS isolation .05 .15 .03 .10 .10 .10 NS NWR .35 .15 .20* .01 .10 .01 Step 3 Constant 14.4 17.9 15.5 11.7 NS elision .75 .16 .49* .46 .10 .46* NS isolation .08 .15 .05 .15 .10 .15 NS NWR .33 .15 .19* -.02 .10 -.02 NS RON -.28 .23 -.10 -.36 .15 -.21*
Note: For NS word reading predictors-R²=.38 for Step 1; ΔR² =.03 for Step 2 and ΔR² =.01 for Step 3. For NS fluent reading predictors R²=.36 for Step 1; ΔR² =.00 for Step 2 and ΔR² =.04 for Step 3. * p < .05;** p < 0.01, ***p < 0.001 (95% confidence interval).
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Results of the regression model in Table 5.7 show that 38% of the variance in NS single word reading was predicted by the model in step 1. In step 2 when NS NWR was entered, it accounted for an additional 3% variance in NS word reading. In step 3, NS RON accounted for an additional 1% variance in NS word reading beyond that explained by PA and PWM measures. NS Elision significantly predicted NS word reading at every stage of the model with significant beta weights (β = .59, p = .000 at step 1, β = .52, p = .000 at step 2 and β = .49, p = .000 at step 3). NS NWR also significantly predicted NS word reading at every stage of the model (β = .20, p = .025 at step 1 and β = .19, p = .035 at step 2). NS phoneme isolation and NS RON failed to significantly predict NS word reading.
With regards to NS fluent reading, a multiple hierarchical regression model showed that NS elision and NS isolation predicted 36% of the variance in this outcome variable at the first stage of the model. In stage 2, NS NWR did not account for any additional variance in NS fluent reading. NS RON (stage 3) accounted for an additional 4% variance in the outcome of fluent reading. NS elision significantly predicted NS fluent reading at every step of the model (β = .54, p = .000 at step 1; β = .54, p = .000 at step 2 and β = .46, p = .000 at step 3). NS RON significantly predicted NS fluent reading (β = -.21, p = .018) at step 3 of the model. NS isolation and NS NWR did not significantly predict fluent reading.
In table 5.8 below, the regression statistics for each of the two groups are presented (with regard to NS reading).
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Table 5.8 Hierarchical regression for within group PP predictors of NS reading
Group 1 (NS group) Group 2 (English group)
NS word reading NS fluent reading NS word reading NS fluent reading
B SE B β B SE B β B SE B Β B SE B β Step 1 Constant 34.3 10.5 .49 8.08 14.5 7.03 13.7 8.4 NS elision .71 .17 .60* .50 .13 .55* .70 .24 .41* .38 .16 .36* NS isolation .04 .18 .03 .09 .14 .10 .45 .23 .29* .25 .14 .27 Step 2 Constant 28.5 13.4 2.32 10.3 26.8 14.5 10.7 9.6 NS elision .68 .17 .57* .50 .14 .54* .58 .25 .34* .41 .17 .39* NS isolation .03 .18 .02 .09 .14 .09 .40 .22 .25 .27 .15 .28 NS NWR .14 .19 .10 .04 .14 .04 .39 .22 .22 -.10 .15 -.09 Step 2 Constant 39.3 23.6 30.1 17.3 23.4 24.8 -3.1 16.4 NS elision .68 .18 .56* .45 .13 .50* .56 .26 .32* .38 .18 .36* NS isolation .03 .18 .03 .10 .13 .10 .40 .23 .26 .29 .15 .30 NS NWR .12 .19 .08 -.02 .14 -.02 .40 .22 .22 -.09 .14 -.09 NS RON -.18 .31 -.07 -.52 .23 -.28* -.06 .33 -.02 .13 .22 .08
Note:In Group 1, NS word reading predictors -R²=.38 for step 1; ΔR² =.01 for step 2 and ΔR² =.01 for step 3 and for NS fluent reading-R²=.37 for step 1; ΔR²= .0 for step 2, ΔR²= .07 for step 3. In Group 2, NS word reading predictors-R²=.46 for step 1; ΔR²=.05 for step 2 and for NS fluent reading
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5.5.2.1 Within-language PP predictors of NS reading in the NS group The results reveal that in Group 1 (NS group), NS elision and NS isolation accounted for 38% of variance in NS word reading at step 1. NS NWR (entered at step 2) and NS RON reading (entered in step 3) accounted for an additional 2% variance in NS word reading. NS elision significantly predicted NS word reading with significant beta weights at every stage of the model (β = .60, p = .000 at step 1, β = .57, p = .000 at step 2 and β = .56, p = .000 at step 3). NS isolation, NS NWR and NS RON did not significantly predict NS word reading in the NS group.
NS elision and NS isolation accounted for 37% of variance in NS fluent reading at step 1. When NS NWR was entered in step 2, it did not account for any additional variance in NS fluent reading. Adding NS RON as predictor variable resulted in the model explaining 44% of variance in NS fluent reading (i.e. NS RON explained an additional 7% variance in NS fluent reading performance beyond that explained by other phonological measures). NS elision significantly predicted NS fluent reading in every stage of the model (β = .55, p = .000 for step 1, β = .54, p = .000 for step 2, and β = .50, p = .001 for step 3). Neither NS isolation nor NS NWR significantly predicted NS fluent reading. NS RON significantly predicted NS fluent reading (β = - .28, p = .028) in the NS group.
5.5.2.2 Within-language PP predictors of NS reading in the English group In group 2 (English group), NS elision and NS isolation accounted for 39% of variance in NS word reading at step 1. After adding NS NWR in step 2 the variables accounted for 43% of variance in NS word reading. Adding NS RON into the model at stage 3 did not explain any additional variance in the NS word reading ability of the English LoLT group. NS elision (β = .41, p = .006 at step 1; β = .34, p = .025 at step 2 and β = .32, p = .039 at step 3) and NS isolation (β = .29, p = .051 at step 1) significantly predicted NS word reading. However, NS isolation failed to predict word reading at stages 2 and 3 (after the variables NS NWR and NS RON were entered into the regression model). NS NWR and NS RON did not significantly predict NS word reading in the English group.
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NS elision and NS isolation accounted for 32% variance in NS fluent reading ability in stage 1. NS NWR (entered into the model at step 2) and NS RON (entered in step 3) explained an additional 2% variance in the NS fluent reading abilities of the English group. NS elision (β = .36, p = .020 at step 1, β = .39, p = .017 for step 2, β = .36, p = .037 for step 3) was a unique predictor of fluent reading ability in the English group at every stage of the model. NS isolation, NS NWR and NS RON did not uniquely predict NS fluent reading ability in the English group at any stage of the model.