Q: How would I add a non-standard word to Dictation?

When doing dictation, I'm frequently using words not in my language's download file. For example, I've named my iMac 'Mizuho' (sounds like me-zoo-hoe), after a character from a Japanese Anime series called Onegai Teacher.  Of course, dictation thinks I want to type 'Me zero' which is, of course wrong so is there a means of educating Dictation about 'Mizuho', 'Onegai', 'Sensei', etc?

Additionally, there is spoken commands in Dictation that I've discovered by trial and error called new-line and new-paragraph, but while I'm happy with the soft-return produced by new-line, I would rather have a Hard-return put into the text stream by new-paragraph, rather than two successive uses of Soft-returns. Can that be corrected as well?