The use of audiovisual aids is necessary for students in the classroom whether in courses of literature or language. We usually use them in the class as they will consolidate the teaching and learning process.
Using audio-visual aids has a great impact in reaching out to those specific type of students who learn best with audio and visual. However what's more important is how you organise your content or lesson. Is is tallying with the device in use? For instance are you only using the projector to beam texts? Or beam a video demonstration of an experiment that would otherwise be difficult to explain from the fact that you have no laboratory at your school? So lesson plans must be in accordance with the aids.