Even students with limited vocabulary can participate in a discussion at a basic level. Discussions force students to make themselves understood by their peers and not just by a sympathetic listener such as the conversation partner.
Discussion I (Arabic)
Here students listen to a song they have not heard before and discuss it.
Discussion II (Persian)
The conversation partner takes a word that the student uses in a response and makes it the core of a discussion. This is a good technique because it takes a topic in which the student has already shown interest and encourages elaboration.