Abstract
This study aims to identify the relationship between the developmental hierarchy in the acquisition of Arabic as a second language (Arabic L2) and formal classroom instruction. It provides a general presentation of the current debate on the influence of formal instruction in the acquisition of L2. Special attention is given to the subset of Processability Theory (PT) known as Teachability Theory, and its implications for teaching methods of L2 in general and Arabic L2 in particular. This study also provides descriptive information on teaching objectives and materials used by the participants to study Arabic L2. This information is presented in order to establish an explanation for the connection between the formal teaching of Arabic L2 and the processability hierarchy. Participants were nine students studying Arabic as a second language at the Australian National University (three Beginners, three Intermediates, and three Advanced). Interviews were conducted over a period of two teaching semesters during the year 2005. Both implicational and distributional analyses were conducted. The results of these analyses show that teachers and curriculum developers should consider the PT's predicted developmental stages for Arabic L2 structures when developing teaching materials and syllabus.