Adopting a semiotic approach to technology-mediated language teaching may constitute an appropriate perspective to grasp some of the issues pre- and in-service teachers have to deal with when they integrate technology in their pedagogical practice. With reference to the seminal work of Halliday (1978) and Van Lier (2004), we will see how this perspective has fueled research on language learning (Pinnow, 2011) and language teaching (Jewitt, 2009) and how it can help understand how language teachers’ postures are challenged by the use of technology and how technology can progressively become part of their semiotic repertoire. Semio-pedagogical competence will be defined as a key competence needed by language teachers to effectively work in the digitally enhanced language classroom. To illustrate how this competence can de developed through training, I will present a telecollaboration project between Lyon and Dublin whereby future teachers of French as a foreign language prepare and participate in online interactions with learners of French in a business school in Ireland. Certain aspects of this project will help uncover the challenges that are at stake for teachers who are confronted with a dense multimodal situation (Norris, 2004) and it will give me the opportunity to present the concept of “critical semiotic awareness”.