Ok, so I've been reading よつばと recently, and I've been seeing a suffix coming up that I cannot seem to find a meaning for. It's not in any dictionary, and I'm not sure if it's a name suffix, or some obscure grammatical marker I've never heard before. Here's an example:
What does the ち after おばあちゃん indicate? Is it actually doing something in the sentence, or is it a soft version of ちゃん? That's my hypothesis, but I'd like confirmation.