Figure 2:

Stripcharts showing the distribution of VOT values for each of the participants, grouped by language (with Mandarin speakers in the left panel and English speakers in the right panel) and by gender within each language. The black diamonds represent aspirated/voiceless stops (which are analyzed in this paper), and the grey shaded dots are for unaspirated/voiced stops (the analysis of which is beyond the scope of the current paper, as noted in the main text). In the panel on the right, the numbers {13, 1, 16, 2, 7, 2, 5, 5, 9, 9, 3, 2, 3} above the subject IDs for five of the females and eight of the males are counts of voiced tokens with lead VOT. Boxplots in the center of each panel show the median, inter-quartile range, and range for each gender and stop type. (The whiskers for the minimum VOT for English voiced stops are well below the bottom of the plot, due to the 77 tokens with voicing lead.)