It sounds like she has some personality issues, but as someone who has lived in a bunch of different countries, I can attest that sometimes I forget how to pronounce certain words, and something weird can come out every once in a while. It’s rare, but some close friends and family have noticed and rightfully made fun of me for it. I really wouldn’t have noticed unless they pointed it out.
And don’t get me started on spelling…living in the UK for a while totally ruined my confidence with English spelling and turns of phrase. I also still say ‘cheers’ in lieu of ‘thanks’ more than I’d like to admit, and I’ve been back in the US for almost 8 years…
So yeah, your coworker sounds like a trip, but language is so goddamn confusing it’s totally possible that she has no idea how she sounds. Could also just be looking for attention, as others have suggested.