Flashcards with words, phrases, sentences and particular target language culture specific data (like dates, names of important people, places, events, etc.) charts, tables of grammatical rules, posters with various pictures and maps can provide a visual impact for language learning and linguistic performance at the same time.
The projection of PowerPoint images – texts and pictures - (i.e. slides) is taking over the role of projected images that used to be provided by outdating technologies of the 1950s, 60s and 70s like slide-projectors.
The reason why the role and function of the OHPs have not been taken over by digital technologies is that OHP offers a more flexible opportunity for involving students in placing traces of their linguistic performance on the projecting surface spontaneously and you do not need extremely expensive and sophisticated equipment. A further advantage of the good old OHP is that there is no other technology that would let you exploit the educational potential of the so called shading technique when the silhouettes of various objects placed on the projecting surface can encourage students guess, predict, describe the vision, i.e. verbalise their thoughts.