Which of the following does NOT belong to the elements that influence lipreading difficulty?

The aspect that does not belong to the elements influencing lipreading difficulty is visual memory retention. Lipreading relies more on the ability to accurately perceive and interpret visual cues from the speaker's mouth, face, and body language, rather than the ability to retain those visual memories for an extended period.

The listener's residual hearing, speaker’s body language, and message length directly impact the effectiveness of lipreading. Residual hearing can provide additional auditory cues that may aid in understanding spoken language. The speaker’s body language includes facial expressions and gestures, which can enhance the comprehension of the spoken message. Message length plays a role because shorter messages might be easier to lipread due to reduced complexity, whereas longer messages may present more challenges due to the increased number of visual cues to decode.

In contrast, visual memory retention is more about how well one can remember and recall visual information after observing it, which, while important, is less directly related to the immediate challenges faced when lipreading in real-time communication.