Numerous studies show a close relationship between vocabulary and conceptual development, complex linguistic skills and reading comprehension in individuals. However, it is known that not all students start school with the same lexical knowledge, which can be an academic disadvantage for some in relation to their peers. As a response to the aforementioned problem, this article presents the design, implementation and evaluation of a didactic project aiming to increase vocabulary learning skills in adolescents in third grade of secondary school through the teaching of morphological word analysis strategies. An experimental group (19 students) participated in the focal didactic project and a control group (19 students) took part in another language project. To evaluate the effectiveness of the didactic project, both groups completed a pre-test and a post-test on morphological word analysis. The results of the experimental group show a statistically significant increase both in the ability to segment words in their morphemes and in the ability to extract the meaning of words and morphemes, while the results for the control group do not show significant differences.

Vocabulary development; Mother tongue instruction; Educational projects; Secondary schools; Morphology.