Great questions, Kim. Here are my thoughts.
at my children’s ages do you repeat the dictation sentence if they didn’t catch it the first time? How fast or how slow do you go?
I try to give short enough phrases that I don’t have to repeat anything (bolstering the habit of attention, you know 
). So if the exercise was, say, Book 1, Exercise 59, I would break it up into chunks something like this: “Sherlock Holmes” . . . “had been leaning back” . . . “in his chair” . . . “with his eyes closed” . . . “and his head” . . . “sunk in a cushion.” etc. I try to keep the proper inflection in my voice so each phrase isn’t considered the end (very hard to communicate here in writing!). Basically, I watch my child’s writing closely. When she gets almost to the end of the last word I’ve given her, I feed her the next phrase.
I’d also like to know if you let the child study the passage first and then do dictation with him/her?
Yes, yes, yes! In the CM method, the goal of dictation is correct spelling. So look over the exercise with your child first and together identify the word(s) that she is not positive she knows how to spell correctly. Those are the words to study. Once she’s sure (and you’re sure) she has learned those spellings, encourage her to look at the rest of the passage too, including the capitalization and punctuation. Then when the passage has been thoroughly prepared, do the dictating and writing part. What you want to avoid is having the child guess at the spelling and potentially see the word misspelled, which is what “cold turkey” dictation can lead to.
CM dictation is almost like the spelling lessons most of us grew up with: look at the list, study the words you don’t know, write the words on a test. But in CM dictation, you’re using interesting ideas and whole thoughts in context rather than a list. Does that help?
