Short-term memory (STM) is required for second language learning. However, it is not clear what components of STM are necessary for the acquisition and lexicalisation of new written words. Studies suggest that memory for serial order is a critical cognitive process in spoken word acquisition although correlated mechanisms such as executive control also play a role. In this study, bilingual Cantonese–English speakers who are learning written expert words in a non-native language were tested over a one year period in their first year of instruction. Written word lexicalisation was measured using lexical decision and spelling to dictation tasks. Results showed measures of executive control (Stroop performance) and serial order memory capacity predict recognition and recall of written expert words at different stages. Whereas serial order memory predicts improvements to lexical decision accuracy, executive control predicts spelling to dictation performance after one year. The conclusion is that STM processes do constrain written word lexicalisation in a second language. However, executive control and serial order memory capacity have differential effects during word lexicalisation.

The current study investigated the role of cross-linguistic influence in Cantonese–English bilingual children's comprehension of subject- and object-extracted relative clauses (RCs). Twenty simultaneous Cantonese–English bilingual children (Mage = 8;11, SD = 2;6) and 20 vocabulary-matched Cantonese monolingual children (Mage = 6;4, SD = 1;3) completed a test of Cantonese RC comprehension. The bilingual children also completed a test of English RC comprehension. The results showed that, whereas the monolingual children were equally competent on subject and object RCs, the bilingual children performed significantly better on subject RCs. Error analyses suggested that the bilingual children were most often correctly assigning thematic roles in object RCs, but were incorrectly choosing the RC subject as the head referent. This pervasive error was interpreted to be due to the fact that both Cantonese and English have canonical SVO word order, which creates competition with structures that compete with an object RC analysis.