Extended Data Fig. 3: Similar peak HFA response across native and foreign speech conditions.

A. Across Spanish, English, and Mandarin speakers, a majority of electrodes are responsive to both native and foreign speech conditions (purple) as opposed to only native (blue) or only foreign (red) speech. Each scatter point corresponds to a single electrode. HFA peak response is calculated as the peak magnitude of the average response across all sentences in the same language. Average HFA peak magnitudes are correlated across speech conditions (Pearson r(472) = 0.94; r(334) = 0.9; r(77) = 0.9, ***p < 0.001 for all participant groups). B. Spanish, English, and Mandarin speakers show no consistent bias in the proportion of electrodes that are only responsive for only either native or foreign speech conditions (blue, red bars). C. Speech responsive electrodes to one language but not the other showed significantly smaller HFA amplitude responses. Electrodes responsive to only foreign or native speech showed no consistent bias in HFA amplitude and no consistent anatomical location (data not shown). Two-sided Wilcoxon rank sum test (n = [705; 113; 65]) determined significance between the distribution of HFA peak magnitudes across groups (***p < 0.001). Box plots show the maximum and minimum values (whiskers), median (center line) and the 25th to 75th percentiles (box limits).