How long ago "recently" is is totally subjective; the definition did NOT specify that it had to be a week or less. I would say that "recently" is at least a couple of months, and since my Mojave was installed ONE month ago, that counts as recently… None of which has any bearing whatsoever on the ISSUE.
In case you're wondering if anyone from Apple ever reads on this forum, it turns out that they do, because Roger has gone from being dictated wrong 100% of the time to dictated RIGHT 100% of the time, and I have not changed or updated anything, I have not restarted my computer or even my browser… so it HAS to be on their end. (Apple person, should you return to this thread, thank you so much!)
However, P Phillips, I'm still VERY grateful to you for what you showed me in System Preferences, because I frequently dictate other names, and street addresses, that dictation routinely generates as similar-sounding words, so what you showed me will actually be quite useful!