Cummins' model (see Figure 1) consists of two intersecting continuums: the first from context-embedded language to context-reduced language, and the second from cognitively undemanding language (which requires little conscious attention to language forms or choices) to cognitively demanding language (which requires the active cognitive efforts of the speaker/writer to produce). (Thomas and Collier Research)

While these teachers often overestimate ESL students’ academic level of proficiency, Emily’s description (below) suggests that she is aware that while the students have a good grasp of BICS (context-embedded language), they lack CALP (context-reduced language). Her contention is that this will prove particularly problematic for the students the following year in high school. (Lynne Wiltse)

According to Cummings [p115] the cognitive demands placed on underprepared second language students, are intensified not only by the fact that they are studying in the second language, but rather, that the context-reduced language they encounter in lectures, relies on linguistic cues to meaning, and the successful interpretation of the message itself, depends heavily on the knowledge of the language. (Commonwealth of Nations)