Compare and Contrast the Stages
The first two stages involve the development of social language (BICS).
The third and fourth stages incorporate the addition of academic language (CALPS).
It is important to note that content area learning does not come into play until the fourth stage. Prior to this stage, students are in the "learning to listen, speak, read and write stage". It is not until the fourth stage that students are able to "listen, speak, read and write to learn".