This cartoon is a double entendre. Double entendre is open for misinterpretation. Usually one interpretation is risque or at least rude in some fashion. One interpretation may be metaphorically a dog whistle. Clear communication uses none of these but as the cartoon below describes how jokes employ all of these techniques. And from Shakespeare, “Jesters do oft prove prophets,” in King Lear.
Language is nuanced. Idioms and usage depend upon the speaker’s and listener’s background and environment. As Parkinson’s disease develops it often robs the brain of the ability to detect the nuance and subtly of language and more succinctly the difference between truth and tease.
When people do not say what they mean, the listener is left with an unwanted task of interpretation and analysis without complete information. In conversation the listener may respond with, “To be clear… (the uncertainty)?” in order to understand the speaker. This is a fair question. It is not a challenge. It is a clarification. Questions left unsaid answered only by the listener may not be the intended thought of the speaker.
Direct speech can be interpreted as rude. Many speakers talk around a thought in hopes the the listener will hear that which was left unsaid and be less offended. Direct speech can be interpreted as confrontational but direct speech cuts through the Parkinson’s fog. Parkinson’s is not subtle.