Do I use unnecessarily big words?

Let me preface with saying generally my mother and I have a great relationship, but lately I've been noticing some things she does that bug me, like dismissing medical and psychological issues I've mentioned mostly.

Anytime I use certain words, my mother is rude & dismissive and tells me to "speak English." Words I used in the past, were for example, when I was talking about our cats being carnivores and not herbivores or omnivores. Today, I was talking about getting a pulse oximeter for something. I believe I have used the would peculiar before and she was the same way.

Am I talking in too big of words? Is complex word choice an Autistic thing? Or is she just being mean about my word selection?