Was your issue her language or her interest in men? Either way, it sounds like you could have handled that better especially if your concern was her being a bad influence on her siblings. Taking your story at face value, your behavior isn't much different than hers if the primary concern was language/tone. Im not going to go to the extreme of the new age soft parenting shit, but indirectly you could be teaching the younger siblings it's ok for a man to speak to/disrespect them. Maybe you said it in a playful manner but the fact that you said she was crying and you felt the uncle may take issue with how you handled it says you likely were disrespectful.
Whatever the reason she felt comfortable speaking like that around you and her mom. Regardless of what the mother said, clearly they have a relationship where the daughter didn't see an issue with speaking like she was amongst her peers. If you don't have a relationship with the daughter, it probably would have been better to bring it to the mom's attention and hsve her discuss the issue. If you felt the need to address yourself, pull her to the side. Even if you raised her, she isn't a kid anymore and to the best of your ability you should attempt to treat her as an adult. I get that regardless of their age you'll always see them as kids.
I don't have older kids or nieces/nephews. However, my younger brother does wild from time to time in the past. For me, trying to talk to him in public would have led to us fighting, so I brought his behavior up once we got away from the rest of the family. He was more receptive and apologized to the family. Addressing him in public probably would have hurt his ego which leads to both of us not wanting to back down and as I stated fighting over a relatively small issue.
Again, my girls are babies, but one of them already gives signs of being a future fast ass lol. I'm hoping to balance enough where they know where the line is and still feel comfortable talking to me about boys/men. I don't want to be the dad who tries to hide them from boys and then they get to college and don't have any experience to know how to move.
