Siri dictation spelling an grammar errors

The other day I dictated a text with the word “visibility” in it. Siri spelled it “Vizza Bility.” Really? What is that? I googled it and it’s not like that’s a famous rapper everyone is talking about or a commonly used alternative spelling or something. In fact, the only occurrences of that spelling are from others complaining about the same thing on their iPhones. (Tweets that have since been deleted, which is also odd.) So where/how did Siri come up with that spelling?

Another common problem is autocorrect changing my correctly typed words into incorrectly spelled words. One example is if I typed, “The Browns are coming,” autocorrect changes is to “Brown’s.” You don’t use an apostrophe to make a plural!

How does Siri not know basic English grammar and spelling?