Captioned Television as Comprehensible Input

A well known theory argues that competence in a second language (L2) is a function of the amount of “comprehensible input” received, without formal instruction in reading or grammar. This study analyzes whether comprehensible input via captioned television influenced acquisition of science vocabulary and concepts. The 129 bilingual seventh and eighth graders were assigned to four groups: (a) captioned TV, (b) TV, (c) reading along and listening to text, or (d) textbook only (control). Treatment groups either viewed or read three units of science segments from the 3-2-1 Contact science series twice a week for 12 weeks. Pretests evaluated vocabulary and prior knowledge; posttests analyzed knowledge of 90 target words and a written retelling. Subjects in the closed-captioning group outscored others in word knowledge and recall of information. An analysis of factors suggested that contexts providing explicit information yielded higher vocabulary gains. Subjects more proficient in English learned more words from context than others. These results suggest that comprehensible input may be a key ingredient in language acquisition and reading development.