For question type 'Drag and drop into image' (qtype_ddimageortext) when 'viewing' as a student using a screen reader (NVDA or Jaws or similar) it is easy to tab to the 'blank slot' and place an answer there, but the screen reader does not give a suitable verbal clue. Similarly for the question type 'Drag and drop onto text' (qtype_ddwtos) the screen reader will read out the question skipping out the visual clues.

For instance if the ddwtos question is 'Mary had a little [[1]], who's fleece was white as [[2]].' then the screen reader says 'Mary had a little who's fleece was white as.'.

This improvement places the word 'blank' (as a language string) in the right places for the screen reader only for these two question types, in order to help improve accessibility. Note the word blank will be used in ddwtos, but for ddimageortext the word blank will only be used if the question author does not give a suitable description.