>Approach the rodent's general area.
>How do we communicate with them?
>If it's just speech, say, "Hey, come out here? I'm a friend."
>You step into the alleyway, and approach the place where you saw the movement. You can hear subtle rustling behind a small pile of boxes.
>You're still capable of producing vocalizations like an ordinary mouse, and this is how you talk to them. It's largely impossible to convey complex concepts this way, but you're fairly good at getting across the essential idea of something, at least as far as a mouse's ability to comprehend.
>You chitter a friendly greeting in the direction of the boxes. A moment later, a small gray mouse pokes its head out from between two of them and squeaks back at you. The sentiment could be roughly translated as: "Holy crap, you're huge!" This is... not an uncommon reaction.
> Bribe it with cheese if necessary.
>At the moment, it seems content to speak with you, and more than a little in awe of you, but you keep this in mind for any future reluctances.