The recognition accuracy (% correct) of the HINT sentences produced by native English male talker (MN), male and female talkers with mild (M1 and F1) or moderate (M2 and F2) foreign accents in the unprocessed and six-channel vocoded conditions. The data for the native English-speaking male talker were adopted from Yang et al. (2022) [37] for the comparison of recognition performance between the native and foreign-accented talkers. The box represents the 25th and 75th percentiles of the performance. The notch represents the median, and the whiskers represent the range. Outliers are plotted with filled symbols.