## 3 Results
### ASR Performance
On the other hand, we tested the non-native minimal pairs utterances with gASR, obtaining a 30.0% WER (16.0% non-recognized words). In the case of the kASR, as expected, the _All_ model reported the best test results (44.22%) for the non-native speech. The _Female_ train model yielded a better WER value for the non-native test model (55.91%) than the _Male_ one (64.12%) since 30 out of 33 participants were female speakers. Table 5 displays the average scores assigned by the gASR and kASR systems to the 3696 utterances of the pre/post-tests classified by the three groups of participants, in a [0, 10] scale. Symbols \(\overline{n}\), \(N\), and \(\Delta\) refer to the mean score of the correct pre/post-test utterances, the number of utterances, and the difference between the post-test and pre-test average scores, respectively. The students who trained with the tool (experimental group) achieved the best pronunciation improvement values in both gASR (0.7) and kASR (1.1) systems. Nevertheless, the in-classroom group achieved better results in both tests and with both ASR systems (4.1 and 6.1 in the post-test; and 3.5 and 5.2 in the pre-test, gASR and kASR, respectively). The placebo group achieved the worst post-test values (3.2 and 3.5) and pronunciation improvement (\(\Delta\)) values (0.2 and 0.4). Table 6 shows the cases in which there are statistically significant inter- and intra-group differences between the pre/post-test values. A Mann-Whitney U test found statistically significant differences between all groups and with both ASR systems in the post-test. Although there were significant differences between the pre-test scores of the in-classroom group and the experimental group, and the placebo group, such differences were minimal since the effect size values were small (r = 0.10 and r = 0.20, respectively). Regarding intra-group differences, a Wilcoxon signed-rank test (right part of Table 6) found statistically significant differences between the pre/post-test values of the experimental and in-classroom groups with both ASR systems. In the case of the placebo group, there were differences only in the gASR values. \begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Inter-Group (Mann–Whitney U)**} & \multicolumn{6}{c}{**Intra-Group (Wilcoxon Signed-Rank)**} \\ \cline{2-13} \multicolumn{1}{c}{\multirow{2}{*}{**Groups**}} & \multicolumn{3}{c}{**Pre-Test**} & \multicolumn{3}{c}{**Post-Test**} & \multicolumn{3}{c}{**Post-Test–Pre-Test**} \\ \cline{2-13}  & \multicolumn{2}{c}{**gASR**} & \multicolumn{2}{c}{**kASR**} & \multicolumn{2}{c}{**gASR**} & \multicolumn{2}{c}{**kASR**} & \multicolumn{2}{c}{**gASR**} \\ \cline{2-13}  & \(p\)**-Value** & \(Z\) & \(p\)**-Value** & \(Z\) & \(p\)**-Value** & \(Z\) & \(p\)**-Value** & \(Z\) & \(Group\) & \(p\)**-Value** & \(Z\) & \(p\)**-Value** & \(Z\) \\ \hline EXP-NC & \(<\)0.001 & \(-\)8.892 & \(<\)0.001 & \(-\)3.645 & \(<\)0.001 & \(-\)2.773 & \(<\)0.001 & \(-\)2.886 & EXP & \(<\)0.001 & \(-\)13.784 & \(<\)0.001 & \(-\)5.448 \\ EXP-PLA & - & - & \(<\)0.001 & \(-\)3.42 & \(<\)0.001 & \(-\)3.524 & \(<\)0.001 & \(-\)3.527 & INC & \(<\)0.001 & \(-\)2.888 & \(<\)0.001 & \(-\)3.992 \\ INC-PLA & \(<\)0.001 & \(-\)8.050 & \(<\)0.001 & \(-\)3.431 & \(<\)0.001 & \(-\)6.32 & \(<\)0.001 & \(-\)7.651 & PLA & 0.002 & \(-\)3.154 & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Inter and intra-group statistically significant differences between the scores of the pre/post-tests.