When you live with something for a while, it can be difficult to detect little changes that occur over time. The subtle differences and small tweaks can slip by without notice. I am definitely having this experience with Siri in my daily use over the last few months. I can’t tell you when both Siri and the on-board Voice Dictation started replacing and correcting words after the fact based on grammar rules, but I see that it’s happening on a regular basis now. One direct example I noticed recently would be Dictation replacing “there” with “their” based on the context of the sentence after I had dictated a few more words. I’ve seen the same with “your” and “you’re,” as well. This makes voice dictation far more flexible and usable, since I don’t have to go back and edit as often.