Asking anyone to repeat themselves is tantamount to entering a mine field. Certain responses and outlook are guaranteed regardless of how polite and genuine the request is made and desired.
The first problem to overcome is timing. In a flow of words anyone speaking is almost certainly unlikely to welcome interruptions. Attempting to ask for clarification in this scenario will probably be met with some annoyance and feelings of disrespect will come into effect. i.e: the speaker will feel you're disrespectful by asking before they've completed their comment.
However, attempting to guide someone to a specific area of their lengthy commentary whilst having no real idea of what was said at that point is difficult. Someone with APD may well switch off at that point (attempting to replay what they didn't understand the first time) and missing the rest of the comment entirely.
There are several ways of clarifying comments that will or maybe employed by those with APD simply because they're in general use and mask the problem.
Asking directly, a simple, "What?"
This can be asked in a variety of ways; using tone to cajole, brevity to engage, laughter to assist. Additions are often made depending on the situation, sugar coating to elicit the best possible response and take ownership of the problem - "Sorry, I didn't quite catch what you said...?"
Paraphrasing avoids direct argument and deflates potential aggressive stances, so does prompting similar i.e: "So what you're saying is........ ?"
Lip reading, body language, language parameters, word context, sign language, probability, logical choices all come into use by those with APD along with any background noise, conversation and interest.
