Dont talk to them, at all. They are not there to be your friend. Provide them with ID (if you are required to) and then shut up and lawyer up.
Also, when a cop asks you if he can enter your house, treat him like a vampire. Do not let him enter, walk outside, lock the door behind you if you have to or ask if he has a warrant. If he does not, ask him to leave. If he has a warrant, be nice, obey his instructions, but by all that is holy, shut the hell up until you talk to a lawyer.
Civilian Date: 14 Century
1 : a specialist in Roman or modern civil law.
If you are not subject to the UCMJ, you are a Civilian. I don't care one bit what updated dictionaries say.