The effect of an intervention focused on academic language on CAF measures in the multilingual writing of secondary students

The present study aims to explore the effect of an experimental intervention based on academic writing instruction and scientific argumentation on the argumentative multilingual writing of secondary school students. Complexity, accuracy, and fluency (CAF) measures were used to evaluate the texts. A quasi-experimental study with a pre-test/post-test design was carried out with a control group (n = 49) and an experimental group (n = 63) of Basque-Spanish bilingual Year 8 students. The students composed scientific argumentative texts before and after a science unit was taught. Participants in the experimental group received instruction on academic writing and the discourse aspects of argumentation. The corpus of 678 texts was processed using MultiAzterTest and CAF measures were retrieved. Repeated measures ANOVAs were used to compare pre-test and post-test results. The control group exhibited a significant decrease in some fluency, syntactic complexity and accuracy measures, while the experimental group showed a significant improvement in some syntactic complexity and accuracy measures. These results suggest that the experimental intervention might have had a positive impact on written CAF measures. This study emphasises the importance of teaching academic language in multilingual contexts.