Too Many Words, Too Little Support: Vocabulary Instruction in Online Earth Science Courses

Framing Vocabulary Support For Science Content

Corson (1984) proposed the concept of a lexical bar. This bar is essentially a threshold between common words in English that are usually learned through oral communication during childhood and the academic written language in English learning educational settings. This bar, Corson observed, is easily crossed by some students, but for others, it is a daunting task. For almost all students, crossing the lexical bar requires instruction that explores the lexical nature of academic written language, which includes vocabulary instruction. The purpose of this section is to describe what it takes to cross the lexical bar in terms of science vocabulary, explore the ways in which words that help students reach the lexical bar are identified for instruction, and summarize research on vocabulary support strategies for students with disabilities—a group that has particular trouble crossing the lexical bar.