The present study investigates bilinguals’ capacity to rapidly establish memory traces for novel word forms in a second language (L2), as a function of L2 linguistic proficiency. A group of Chinese-English bilinguals with various English proficiency levels were presented with a reading-aloud task, consisting of 16 pseudowords and 16 English words repeatedly presented across six training exposures. Behavioral and neurophysiological data were collected, and modulations in the word-length effect across repetitions were measured as an index of transition from sublexical to lexical involvement. Results revealed that higher L2 proficiency was associated with decreased word-length effect on novel words, reflected in both naming latencies and early N1 and P200 brain responses. In contrast, lower proficiency learners appeared to engage in effortful letter-to-sound decoding processes, with higher attentional allocation to the letter sequence and greater use of sublexical processing across exposures. Our findings highlight the need to tackle specific grapheme-to-phoneme skills for efficient learning of L2, particularly in populations where the L1 is nonalphabetic.

本研究调查了双语者快速建立第二语言（L2）新词形式记忆痕迹的能力，作为 L2 语言熟练程度的函数。一组不同英语水平的中英双语者接受了一项朗读任务，该任务由 16 个伪词和 16 个英语单词组成，在六次训练中重复出现。收集了行为和神经生理学数据，并测量了重复过程中字长效应的调节，作为从词汇参与到词汇参与的转变的指标。结果显示，较高的 L2 熟练程度与新单词的字长效应降低相关，这反映在命名潜伏期以及早期 N1 和 P200 大脑反应中。相比之下，水平较低的学习者似乎参与了费力的字母到声音的解码过程，对字母序列的注意力分配更高，并且在接触过程中更多地使用词汇下处理。我们的研究结果强调，需要解决特定的字素到音素技能，以有效学习第二语言，特别是在第一语言非字母的人群中。