Robin's on the right track--simple sentences with plenty of specifics. That sort of thing leaves fewer options for Phalanx to stumble over, while putting up guardrails to try and keep the creature on-topic and not spiraling off the road into undefinable territory.

Unfortunately, in this case, it might be a little too specific. If there's one category of things that don't process and stick well in Phalanx's busy brain, it's proper names.

"Skeletons, skeletons. A city of... how long have I been?"

Their tone is very expressive this time, filling in the gaps where the words don't entirely make sense. However long they may or may not have been in this city, they still have no idea what Robin is talking about.