When Hannah was very small she was quite a vigorous signaller of a need to go potty. I loved that I was able to (eventually) understand her signals and provide her a place to go potty other than in her diaper. It took me a little while to figure out some of her signals. Once I figured them out, they were so obvious! If she was in the sling and needed to go, she would start squirming. If she was nursing and starting popping on and off, I knew she had to go. The most obvious times were in the sling and while nursing. Other times she squirmed or fussed and I knew. Gradually she stopped signalling. I wasn't quite ready for her to stop, though! But she also stopped signalling when she was hungry. Many times I just "knew" she had to go.
At the age of one, she really doesn't signal. Sometimes she'll be a little fussy in the morning, and I'll take her and she goes. She will fuss a lot when she has just wet her pants, which definitely is communication. I change her, or nowadays just take off her diaper and let her go nakey for awhile.