In "Language awareness and language learning" (Svalberg, 2007) I concluded that the otherwise diverse and multidisciplinary field of language awareness (LA) is given coherence by its focus on engagement with language. I argued that LA is seen as active and not merely as a state of conscious awareness or sensitivity. This paper goes one step further by developing and testing the construct. It discusses what engagement with language might consist of and contrasts with and how it can be identified. Cognitive, social, and affective aspects of engagement, including notions such as attention, autonomy, and agency, are posited. Having arrived at first at a working definition and then an expanded and refined definition, the construct is applied to some classroom and student interview data. Some tentative conclusions about English for Speakers of Other Languages (ESOL) students' engagement with language, what motivates, facilitates, and hinders it, are drawn. The main purpose of the paper is, however, to try and determine the usefulness or otherwise of the construct as such, how it relates to other constructs in the literature, and where it might be taken in future research. (Contains 2 figures, 4 tables, and 3 notes.)