I think the OP meant words where you actually mix up the letters or something. The trend of pronouncing the ayin the same as an aleph is so mainstream I don’t see the point of mentioning it as a “mistake.” It’s about 100 years too late to try to fix that.
I used to say “nigdol” in the lamnazeiach mizmor l’david every morning. Then, there was another one of these threads on the CR where are poster named papa bar abba mentioned he had made that mistake for years. That caused me to look in the siddur and realize that it’s actually nidgol and I had been saying it wrongly as well.