List of supplementary materials
1. Supplementary figures:
- `figure_s1`: Acoustic data before and after gender normalization
- `figure_s2`: Speaker-wise mean F1 in non-switched English productions
1. Appendix S1: Discussion and references on linguistic situation in India and detailed language background of participants
2. Appendix S2: Discussion on power analysis and sample size in the study
3. Appendix S3: Sequence of statistical models, outputs, and determining the optimal model