I have found that Montessori classrooms vary in their approach to spelling in the elementary (primary) years. This is an idea that I received from a Montessori teacher and have adapted to use at home. I introduced a personal dictionary to Otis when he was almost six and approaching the second plane of development (6-12 years).
When the child first begins to write we do not make corrections with either grammar or spelling, we do not write on the child's work. They have ownership over their writing and it is important to them. We "teach by teaching, not by correcting.” We allow the child to write without judgment, without suggestions, and without corrections.
Otis has a desire to write. Over the school holidays, he put much effort into writing recipes. We would make the recipe and then he would need to make changes and would rewrite the recipe. After the first couple of times asking to spell 'flour' (not flower) and 'vanilla' I decided to put these words into his personal dictionary. We are using an Early Years Dictionary, each letter has a few words already written in it, and it has space, in some cases an entire page for you or the child to write their most asked for words. I do not want Otis to become reliant on the dictionary but rather use it as a tool when he feels stuck or when he knows the word but just can't remember. It allows the child to help themselves!
It also teaches the very basic and beginning steps of learning how to use a dictionary and for Otis, it is reinforcing the order of the alphabet. The words we put into his personal dictionary are important, have meaning to him and are used frequently.
Here are a couple of other recommendations on how to use a personal dictionary in a Montessori environment.
A child’s personal spelling dictionary: In Montessori classes the child constructs his “spelling dictionary” of words that are a part of his individual writing vocabulary. For this you can use a simple address book, preferably one without any writing in it, just the alphabetized tabs. But since such books are not much used these days it is better to make one by cutting tabs into the pages of a small notebook, or buying alphabetized tabs to fasten to the pages. Whenever a child comes to you for the spelling of a word, or if he asks you to check the words he has written and you find some misspelled, write these words—beautifully of course because you are the model for writing —in his spelling dictionary, words beginning with 'a' in the 'a' section and so forth. The next time he wants that word he will be able to find it in his own book. - Michael Olaf
For Spellers Moving Beyond Phonetic Spelling Towards Some Sight Words (around age 6-8): Do: use an individual spelling dictionary at home. You can use a mini address book and place words they want/need in their dictionary. Sight words (once, of, was) can be written on both the correct page, AND the page where your child thinks it would be ("once" on page w, "of" on page u). - Aquinas Montessori School
This is a lovely example of a Personal Dictionary at L'école des amours!