Answer:
elderspeak
Step-by-step explanation:
Based on the scenario being described within the question it can be said that Mr. Rizk is being subjected to elderspeak. This term refers to a unique speech style in which younger adults speak to older adults using simpler vocabulary and sentence structure, and many times in a louder-than-normal volume. Such as the individuals at the post office are doing to Mr. Rizk thinking that Mr. Rizk would only understand them if they speak that way.