This study focuses on the Moroccan Arabic language variety of Ksar el Kebir, characterised by a peculiar absence of vowel quantity opposition, which is not shared by the other Moroccan Arabic varieties. Strongly affected by the prestigious Standard Arabic though, the educated informants are aware of a duration opposition between vowels. The study then examines gender differences in Moroccan lexeme perception and the emergence and development of this distinction during the primary and secondary school years of the youth of Ksar el Kebir.