Within a Sheltered Instruction Observation Protocol (SIOP) lesson, teachers present content in ways that allow English Language Learners (ELLs) access to the critical concepts of a curricular area. There are several components to a lesson within SIOP but the point of departure is the activation and building of background knowledge. Activating and building background knowledge includes developing the key English vocabulary related to the content.
Emphasizing vocabulary as a first step of a lesson makes sense in that different languages use different words to represent the same concepts. Students may already have the concept in their native language or at least some relevant background knowledge to the concept. By emphasizing the key vocabulary for the content at the beginning of a lesson, teachers ensure that ELLs access, elaborate upon, and/or develop concepts the core concepts of content curricula.
ELLs who participated in the SIOP model have been more successful than students in non-SIOP classrooms on an expository essay-writing task that is similar to the one that students (including ELLs) must perform in standards-based classrooms (Echevarria, Short, & Powers, 2006).
To learn more about the role of vocabulary in the SIOP model:
Echevarria, J., Short, D., & Powers, K. (2006). School reform and standards-based education: An instructional model for English language learners. Journal of Educational Research, 99 (4), 195-210.