Thinking through the non-native language: The role of private speech in mediating cognitive functioning in problem solving among proficient non-native speakers

Extending Vygotsky's theory and research to non-native language speakers, the literature available to date has provided inconclusive findings on whether L2 speakers use the non-native language to mediate thinking in problem solving. Avoiding limitations in previous studies, the present study investigated private speech produced by non-native speakers with the objective of discovering whether the non-native language can be effectively used as a medium for thinking just as the L1. Non-technical highly challenging multi-level problem-solving activity was utilized to collect private speech from four native speakers and seven L2 speakers of English. Data analysis focused on examining the characteristics of private speech in order to assess cognitive mediation in the L2. The results provided strong evidence that proficient speakers - with extensive formal and informal language acquisition experiences - used the non-native language to mediate their thinking and, unlike in previous research, there was no reversion to the L1.