# An Acoustic Way to Support Japanese Children's Effective English Learning in School Classrooms
## 3 Results and Discussions
### English Test  
The correct answer rate \(p_{\rm c}\) is shown in Table 5, of which the list is sorted according to the difficulty levels in ascending order. The mean correct answer rates were 94.2% in Level 1, 73.7% in Level 2, 50.6% in Level 3 and 22.3% in Level 4. The word pairs categorized into the Level 4 indicated extremely low correct answer rates. Note that chance level in a two-choice forced task, like our English test, is 50%. Nevertheless, the Japanese native children yielded much lower, \(p_{\rm c}<50\%\), with some word pairs. This finding would imply the existence of a bias effect caused by the difference between Japanese and English phonemes and/or lack of English knowledge. All explanatory variables in Table 3 were selected for the multivariate logistic regression model after applying variable selection based on the AIC minimisation. The Odds Ratio (OR) and its 95% Confidence Interval (CI) of each explanatory variable in univariate and multivariate logistic regression analyses are shown in Table 6. An OR greater than 1 implies a positive association with an increased correct answer rate, whereas an OR less than 1 implies a negative association. The bootstrap validation result is shown in Table 7.  
Figure 4: Transfer functions realised by two systems (**(a)** System A, **(b)** System B), both measured by using ESS method (Section 2.4) in the unoccupied furnished English room on a day in December 2019. x-axis: frequency (62.5 Hz to 16 kHz, but unshaded for 125 Hz to 8 kHz), \(y\)-axis: magnitude (\(-35\) dB to 25 dB), depicted with 1/3 octave windowing function in Systune pro (AFMG, Berlin, Germany). Obviously, the most powerful predicting factor for the correct answer rates \(p_{\rm c}\) was the difficulty level of word pairs. In the multivariate analysis, correct answer rates \(p_{\rm c}\) of the second week were better than those of the first week, indicating that many children did indeed get used to the task over those two weeks. Additionally, sound amplification system type also improved the correct answer rates \(p_{\rm c}\) to a certain extent. In regards to seat positions, those who sat on the seats located at the back of the classroom (Seat Group 4-5) performed worse than those whose seats were located in Seat Group 1 area. The habituation effects during single lesson is uncertain in the results at this point. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Word 1** & **Word 2** & \begin{tabular}{c} **Correct Answer** \\ **Rate \(p_{\rm c}\) (\%)** \\ \end{tabular} & \
\begin{tabular}{c} **Number of** \\ **Samples** \\ \end{tabular} &
\begin{tabular}{c} **Difficulty** \\ **Level** \\ \end{tabular} \\ \hline light & right & 17.2 & 412 & 4 \\ long & wrong & 20.6 & 413 & 4 \\ tim & tin & 21.8 & 412 & 4 \\ pull & pool & 33.4 & 413 & 4 \\ \hline tennis & dennis & 41.9 & 413 & 3 \\ track & truck & 48.9 & 413 & 3 \\ top & top & 52.4 & 412 & 3 \\ coat & goat & 59.1 & 411 & 3 \\ \hline cap & cab & 63.8 & 412 & 2 \\ class & glass & 69.6 & 411 & 2 \\ men & men & 71.2 & 413 & 2 \\ sheep & cheap & 73.1 & 412 & 2 \\ fool & fool & 74.3 & 412 & 2 \\ lock & look & 74.8 & 412 & 2 \\ cot & pot & 75.3 & 413 & 2 \\ bin & bin & 77.7 & 412 & 2 \\ car & cow & 78.2 & 413 & 2 \\ cart & card & 78.9 & 413 & 2 \\ \hline bag & bug & 83.1 & 413 & 1 \\ snore & snow & 83.5 & 412 & 1 \\ vine & wine & 84.3 & 413 & 1 \\ pot & pot & 87.1 & 412 & 1 \\ bell & bell & 88.6 & 413 & 1 \\ could & could & 88.9 & 413 & 1 \\ pear & bear & 90.8 & 413 & 1 \\ Bobby & Bobby & 93.0 & 413 & 1 \\ cab & cab & 94.2 & 413 & 1 \\ pig & peg & 94.7 & 413 & 1 \\ wood & good & 96.1 & 413 & 1 \\ ten & pen & 96.6 & 412 & 1 \\ pat & pat & 96.6 & 413 & 1 \\ cup & cup & 96.6 & 413 & 1 \\ fan & fan & 96.6 & 413 & 1 \\ jeer & jeer & 97.8 & 412 & 1 \\ hill & hill & 98.1 & 413 & 1 \\ sand & sand & 98.8 & 413 & 1 \\ walk & walk & 99.0 & 413 & 1 \\ wig & fig & 99.3 & 412 & 1 \\ cut & cut & 99.3 & 413 & 1 \\ toy & toy & 99.3 & 413 & 1 \\ jam & yam & 99.3 & 413 & 1 \\ rack & rock & 99.8 & 413 & 1 \\ \hline \hline \end{tabular}
\end{table}