I get the frustration. Sit in it, spend some time there and look around. So that when you’re done with it, you can be ready to move on and you’re not dragged back into that space in the future because you’ve made peace with it.
I also think you already know exactly what to say, because you just said it in your question.
Here are some things to think about when people ask if you speak your own Native language.
You could say:
“I feel insulted and frustrated when people ask me this because it puts the fault on me, when in reality, the loss of Indigenous languages is a result of colonialism and the very real efforts of many to try and completely wipe out Native people.
“The forced relocation, assimilation efforts through missions and boarding school used harsh punishments and extreme violence for those caught speaking or practicing their Native traditions. This has contributed to the loss of Indigenous languages.”
Now think about what you’d like to do next and perhaps soon you could be saying all of the things I just mentioned, but then add “Because of this I am reaching out and now can speak a few words of my Native language…”
You’ve got this!