Language development in the first language is not yet complete at the beginning of adolescence. Particularly, vocabulary, sentence structure and textual competence develop considerably in secondary school.
Until fairly recently, it was assumed that language development in the first language was completed at the end of childhood. However, research in recent years clearly shows that this is not the case. Language development in the first language is more subtle in adolescence and proceeds in less perceptible ways. And yet important developments are still taking place.