Fig. 2.
Effect of proficiency on L2 phoneme encoding. (A) Phoneme distance maps (PDMs) based on the TRF Ph weights at electrode Cz and peristimulus time latencies from 0 to 600 ms. Blue and red colors indicate phonemes for L1 and L2 participants, respectively. (B) Distance between L1 and L2 phonemes for each language proficiency group. A significant effect of proficiency was measured on the L1-L2 phoneme distance (one-way ANOVA, F(1.4, 54.1) = 22.8, p = 1.6*10−8). Error bars indicate the SE of the mean across phonemes. (C) Distance between phoneme pairs for each proficiency level. The left panel shows results for contrasts existing in English but not in Standard Chinese; in these contrasts, we expected increasing discriminability with proficiency due to learning. The right panel shows distances for contrasts that exist both in English and Standard Chinese; in these contrasts, we did not expect a learning effect. Values were divided by the distance for L1 participants. Gray lines indicate the mean across all selected phonemic contrasts. (For interpretation of the references to color in the text, the reader is referred to the web version of this article.)