You should take as long per passage as is needed to be able to do it correctly. Mistakes DURING dictation should be rare; most of the work should be done before. I typically did two per week. If you are taking longer than one per week, I’d back off down a level; the passages may be too difficult.
We studied a passage daily until they were ready to dictate it. I had one child who was not naturally a visual speller. But good spellers ARE visual spellers. So I simply trained him to do it. Took a little more time, of course, but this is a foundational skill. I worked on other ways to work on visual memory, like lining up picture cards, having him study them, then taking the cards and having him put them back. We took “snapshots” of things around us, then he closed his eyes and told me what was there. We played that silly shower game where you put a bunch of items on a cookie sheet, let him study it, covered it up and he had to list as many as he could. We played Concentration. As he got better at his visual memory, we focused on the words. What do they look like? I often printed one up in a big font. Having trouble with “broccoli”? You could try to memorize the made-up rules that the phonetics folks insist exist (even though we only made them up after the spelling became standardized) and you’ll forever have trouble with which letter is doubled. If you look at the word and think of all the rounded letters, just like the little nubs on broccoli, with only two “stems” sticking up–well, you can spell it when you are 90 in the nursing home. “Accommodating” is another problem word. Well, we know from Latin that it is “ad” plus “com” plus “modus”; and knowing the rules for combining words in Latin, well, of course you would make the “d” into another “c” and there are two “m’s” for “com” and “modus”. Well, so we’ll never spell it wrong! Once you’ve done something like this with all the problem words, ,THEN you are ready to do the dictation and the chances should be small there will be a mistake.
