Content and language integrated approaches advocate the inclusion of “Knowledge About Language” (KAL) in teacher training (Echevarria, Vogt, & Short, 2013; Love & Humphrey, 2012). Content teachers and their professional developers need to see the relevance of KAL for each particular subject and understand language as a meaning making tool. In practice, both groups tend to limit their language focus to subject vocabulary (Phillips & Norris, 2009). Therefore, to broaden teachers’ understanding of the scope of academic language, KAL needs to be specified. One strategy to do so may be with the tools offered by systemic functional linguistics (SFL) (Halliday, 2004; Rose & Martin, 2012; Seah, Clarke, & Hart, 2011; Christie & Derewianka 2008). SFL is receiving growing attention in Europe, but widespread acceptance is lacking because its complex metalinguistic terminology puts high demands on content teachers and can lead to resistance. This paper reports on an educational design research project (Van Aken & Andriessen, 2011) in science teacher training in the Netherlands in which an inventory of science language was constructed collaboratively by linguists and science pedagogy experts. The science lab report (hereafter Practical Report) was chosen as an important text type that reflects substantive science content and epistemic knowledge. An SFL-based analysis of lab reports as a genre was adapted in the Practical Report Analysis Inventory which provides task demands that teachers can use to select specific aspects of science language, explicate these aspects during instruction, and provide feedback to students in their scientific writing. We argue that to be successfully included in a content teacher training curriculum, selected KAL should meet three criteria: relevance—be relevant for the subject, comprehensiveness—reflect a functional and integrated view of language, and manageability—be straightforward in wording and in practical use for teachers when planning and delivering lessons.