I feel exactly the same way and have had a very similar experience. Thank you for sharing your story. They don't teach the Wales dialect in the classes and immersion programs, yet I was learning what I could and felt grief that I still couldn't communicate with my gram. She encourages me to learn any dialect though because I think we have similar language sounds and structures like you mentioned, just said a little differently. We can do something. I feel a calling to somehow support our language teachers and our language speakers (sometimes speakers don't know how to teach, but we can help them share what they can). This drive to learn the language is spiritual. Good luck on your language journey. You are not alone.