The Linguistic European Policy stresses the importance of linguistic diversity and encourages students to learn several languages, believing that the more languages we know, the better we can understand each other and preserve our languages. To preserve diversity and to value all the languages (either included in the curriculum or not) is a first step to develop a plurilingual and intercultural competence in the classroom as a means of overcoming frontiers between languages and between people. A second step is to work with teachers and to value what they know by helping them to find new and innovative answers to meet these professional challenges. Thus, this paper describes the work within a project for professional development of a group of in-service language teachers. The teacher education programme suggests a "portfolio-oriented language learning and teaching approach" that promotes plurilingualism. We will analyse the teachers' starting point and their willingness to work within an innovative and challenging approach. The analysed data include a questionnaire prior to the starting of the programme and three written reflections at the end of the programme concerning professional development, new concepts, teaching approach and working habits. The conclusions indicate that the teachers were not familiar with either the concept of plurilingualism or the "portfolio-oriented language learning and teaching approach". Nevertheless, they clearly show their willingness to try a new approach in their teaching practice. (Contains 3 tables and 1 note.)