Official Everybody Edits Forums

A chat bubble sign would look like a bubble (no arrow) with 3 dots on it, like the sign. But the block would expand revealing a message when you go directly one block below it. An arrow would appear over the player. There would also be another variation of it (with the arrow at the bottom) that activated when you went near it.
You could maybe even have a third variation that initiated a conversation when you clicked the speech bubble. It would be like the second variation, but if you clicked it, you would get responses to the bubble, and varying responses out of those. Of course it would be complicated to set up, but I see it much better than you just reading plain old signs and jumping.