No doubt she misses her mother and probably is confused about why her mother just gave her to you guys full time. She doesn't know how to process that, though, so she does what she can, which is talk about her a lot.

Right now, it's her only connection to her.

I don't really have any advice. I never cared how much SD talked about BM, I let it go in one ear and out the other, as if she was talking about a random stranger.

Echo above really verbally hit that kid up side the head but sometimes that's what it takes.

You might want to bring the subject up while in a calm state and start with "I know you love your mother but..........". Repeat as necessary - he'll get tired of hearing it.

Kids go through stages, the most common one is the question with every answer followed by "why". Likely this kid will finally catch on and quit but Echo's treatment might bring it on quicker. Echo is probably right in that she didn't realize the kid did thinks everyone loves Mommy. After all the kid did and just assumed.

Finally after telling him a few times follow up with time-out in his room every time he does it.

Going through the same thing...
It's a tough call because you don't want to be completely heartless, but at the same time, you don't want to hear about THAT woman at all.
I hope it clears up. I try to ignore my SS4 when he does.
Last night I told him he doesn't need to compare everything I do to his mom and that everyone does things differently, or lots of people like "that" song...

It doesn't get better when they get older. My MSS22, whenever we are together has to mention BM every other sentence. I have been with them 11.5 years. "Mom said this...when mom and I were here,... well, mom says that we should..." ugh!!! They have a pathological relationship. She is still single, and needs dates to go to this cover band, try this restaurant,... He is also her designated driver when she goes to parties with her friends. It is pathetic. I can't believe that MSS's girlfriend doesn't say anything.
Good luck!

Another option could be mentioning YOUR mom's tastes/behaviors etc in reply? Skids tend to not be interested in our little anecdotes about our extended family -- unlike biokids. You constantly bringing up your own mom's alleged adventures in response will so bore her that it might stop her touching on the topic of moms at all.

I was hoping it was maybe a 5 or 6 year old thing (22 years old like the SS above - oh crap! lol) , because my SD aged almost six does this ALL THE FRICKIN' TIME and it is so annoying. Like you say, it's just random stuff. Mine doesn't have the excuse of missing her mum for long periods, because she's only with us a few times a week. I get the feeling she's sort of testing the water to see how we (I in particular) react, as she always looks to me, rather than to my own daughter or DH for a reaction. Depending what mood I'm in I either ignore it totally, or just respond, "oh, right..." or something like that that won't lead to any further conversion about it.

It is a learning process for them. When ex and I broke up 2 years ago, BS then 5 tried talking about how great dad was, because he thought that would get us back together. He then bad mouthed exes new GF to me as he hoped I could tell ex, ex would get rid of GF and I would go back. That was a tough one as ex was convinced I was just jealous of the new GF and putting BS5 up to it, but once he figured it out (a face to face conversation, where I think my expression when he said I wanted him back did more talking than words could!) we worked through that with BS then 5.

Now, GF has repeatedly talked to BS7 about how I do not like her and she does not know why. Not sure if she wanted sympathy?! Anyway, BS7 seems to have taken this as I do not like her and constantly goes on about how mean she is blah blah blah. I sat him down and told him that he is an intelligent boy, I know his game, he already has my love and is not going to impress me by these stories, equally I am not going to love him more because of them, if anything it was annoying me. My son is emotionally very clued in and realized he was pissing me off. I told him there are times he can come to me and there are some things that are unnecessary. I think he gets it. Part of my problem is BS7 loves to talk, so will come up with any topic!

I have also had to explain how dad and GF have cell phones and my number, and if they want me to know something they know how to tell me. I think when they are made messengers it gets worse.

Also, I have noticed if there is any emotional stresser, BS7 ramps up his talking - I think it is his way of processing and I am being used as a sounding board.

It is annoying, but I just laugh it off most of the time...and then you get the gems like this weekend "GF was very mad at ex because their bank account is negative and they both were yelling about who did it". Sure my ex and GF would stop trying to pass messages through him if they realized this means he tells me everything LOL

Tell her "Mommy" is a swear word! Urgh I know how you feel...