<human>: This has been going on for a while (I've been living with them for the past 2 years) and it didn't really bother me in the beginning, but the annoyance has accumulated over time, especially because I thought we were friends by now. They can both speak perfectly good English, and while they did ask me if I was okay with them speaking Cantonese when I moved in (which was fine, it would be unfair to stop them), I'm getting increasingly annoyed because they don't even hide it when they're talking about me.

I know for certain it's about me because whenever me and the older sister come to a disagreement (often about chores or some random social issue), she will end the conversation abruptly, and bring her younger brother (who wasn't even part of the conversation) to another room to talk for a while, and then come back as if nothing happened. Sometimes it goes on for a while so I just go back to my room annoyed and confused. What really bugs me is she gets her brother to relay her thoughts after they've had their talks, instead of talking directly to me.  

Also I like being throwing sarcastic jokes once I get to know someone, but she seems to get really offended and will just ignore me and go talk to her brother. He's even told me once that she finds me really rude and passive aggressive, so I've dialed down on my sarcasm since.

It all really makes me feel a stranger to them, even after 2 years, and always in the wrong, because her brother will always take her side. This is hard to take because I really like living with them, and most of the time we get along really well. I don't know how to bring this up nicely, since she'll just get her brother to tell me I already agreed to let them speak Cantonese at home... In fact they'll probably go into another room to talk about it once I bring it up.

Provide a brief overview of the text.
<bot>: Housemates talk to each other about me in Cantonese. How do I bring this up to them nicely, or should I just ignore it?