They may have difficulty following lectures in large halls, particularly if the acoustics cause echoes or if the speaker talks quietly, rapidly, or unclearly. People who have hearing impairments may find it difficult to simultaneously watch demonstrations and follow verbal descriptions, particularly if they are watching a sign language interpreter, a captioning screen, or a speaker's lips. Small group discussions may also be difficult to follow or participate in, particularly if the discussion is fast-paced and unmoderated, since there is often lag time between a speaker's comments and interpretation.