<human>: She is 19 and I'(m) 21, we've been dating for around 5-6 years and have been living together for a little over 1 year. We both live together with my mother.

My SO has always been the type to say whatever she wants to say however she wants to say it assuming she's saying it around people she feels comfortable with, even if it's rude or entirely unnecessary. She says that her grandparents (who she grew up with) didn't care or simply gave up trying to control her speech while growing up, so it's something she's always done as a child and feels that there's nothing wrong with it. 

My mother, on the other hand, is the type that dislikes profanity & rude speech and doesn't engage in it herself. I'll let loose a curse word every now and then and she'll mention it; a simple "oh, sorry" or "my bad" is enough to put her at ease.

My GF says that my mother is "treating her like a child" if and when she asks her not to say profane things (which is very infrequent assuming my SO doesn't curse often). I personally think it has nothing to do with treating someone like a child and more asking someone to stop doing something you personally dislike, much like how someone would ask another to stop clicking their pen incessantly. She doesn't see it that way though and I don't know what I can say or do to help her understand. 

Considering that we're both living with with my mother rent-free and almost all our expenses being paid for (she also has a job) out of her pocket, I think her request of us being mindful around her about profanity and rude speech is entirely appropriate & non-offensive. Even if those weren't the circumstances, I would still believe it was an appropriate and expected request.

This happened earlier last night and she's been passive-aggressive since my disagreeing with her. I don't know what I can do or say to help her understand; can Reddit help me?

Condense the text into a few key points
<bot>: my SO is ignoring me because I disagreed with her that she should respect my mother's request to try and not be profane around her in the house. how do I respond to this?