The document discusses the importance of materials evaluation and design in language teaching. It notes that materials evaluation, syllabus design, and learner assessment are central activities in applied linguistics. Experienced teachers are able to predict how learners will respond to different types of published materials and know what to use, adapt, and supplement. The document emphasizes that language teachers need the competence to make informed decisions about choosing and using teaching materials, as well as developing their own materials when existing options are inadequate.