Your guess is as good as mine: someone would say this if they do not know the answer to a question.
Provide details and share your research! I do also resent the remarks from the dear Aussie commentator who wrote that presumably he must talk to Americans rather than talk with them.
Any time you hear a person using derogatory terminology to substitute for a word or phrase that isn't inherently negative or ugly, that is an example of dysphemism.
Crying over spilt milk: is a situation when you complain about a problem from the past that cannot be changed.
It can be a colloquialism, but it's often more involved.
Other conversational descendants of loqui in English include , , , , and.