This paper presents a professional teacher development model that applies to the field of content based instruction as implemented in Italy. Its recipients are Italian upper secondary school science teachers involved in teaching a non-language subject in English, which is a foreign language for the teachers as well as for their students. Although the language of instruction is not spoken as a second language in Italy, the authors believe that this model, due to the added challenge of working with foreign language students who need to improve their language proficiency and conceptual understanding, will provide useful insight into scaffolding techniques and accessibility processes that can be exploited by practitioners working in second language acquisition environments.