Rationale for Six New Phonograms
Four specific situations occur in the phonogram structure in The Writing Road to Reading (WRTR) that argue for the creation of additional phonograms.
Coding the Vowel Sound in "Would"
The three words, would, should and could are coded in WRTR with a double underline under the phonogram ou and yet another double underline under the letter "l" in each word. Adding a phonogram oul accomplishes three things.
First, it makes would, should, could, plus their deriviatives like should've and couldn't, easy to read once the phonogram oul has been learned.
Second, it removes the need to double underline both the phonogram ou and the letter "l" in the affected words, substituting one single underline instead.
Third, it provides us a symbol for the /oul/ sound that we didn't have before, so we were always putting symbols above of the letters "oo" or "u" instead, since these were the only other spellings of the /oul/ sound (book, push).
Teaching the Phonogram tch
For some reason, Ms. Spalding included the phonogram dge in the 70 phonograms explicitly taught, but not the phonogram tch, in spite of it occurring almost as often in English words. Regardless, the main reason for adding it now is that the phonogram tch also serves as a very useful marker in the OnTrack Reading Multisyllable Method, in that it marks the sound preceding it as almost always being the first vowel sound, that is, the short sound. For that reason it was added to the list of 84 phonograms to be explicitly taught.
Coding an Additional /sh/ Spelling
While WRTR treats the phonograms ci, ti and si as spellings of the /sh/ sound, the spelling "ssi" in words like mission and passion is handled more awkwardly due to her attention to syllable rules. It is much easier to just teach a phonogram ssi instead and children easily incorporate it into the class represented by the other three spellings above. A word like mission is then coded simply as "mi ssion."
Coding the /err/ (air) Sound
This last addition to the phonograms to be taught is more controversial, for a couple of reasons.
The first reason is that it might not be at all accurate in your locale, depending upon the pronunciation of certain words. The key words to compare are marry, marry and Mary. In some areas, the three words are pronounced differently, with the individual vowel letters being distinct in each word. Thus, marry is pronounced with a strong short-a sound, merry with a strong short-e sound, and Mary with a strong long-a sound (or /m/e/r/y/, /m/a/r/y/, /m/ae/r/y/ using the notation here.)
If all three words are pronounced differently, with distinct vowel sounds, then don't add the following three phonograms to the curriculum.
On the other hand, if merry, marry, Mary all sound the same in your area, you will find that it is easier to add the phonograms ere, err and arr to the list of phonograms to be taught and to teach a fourth /err/ sound for the phonogram ar (to cover the case of words like Mary, parent, and arid.) At the same time, the phonogram er can be taught with an additional /err/ sound to handle words like cherish and merit. The phonogram ere is only used in the words there, where and the archaic ere, plus derivatives like nowhere and therefore. Incidentally, all of these situations occur well into the Ayres List.
And finally, note that words that have the /ae/ spellings ai (fair), a-e (care), and ea (bear) can just be taught as having an /ae/ sound followed by a /r/ sound, and are coded the same as in Spalding.
I worked with struggling readers for over ten years one-on-one, and they had no trouble learning to accept the above phonograms. I'm convinced they made explaining the English code easier as well. However, in our area, we hear virtually no difference between merry, marry and Mary.
That concludes the discussion of the various rationale for modifying the traditional WRTR phonogram structure. All of these modifications, incidentally, are incorporated into the OnTrack Reading Advanced Code Phonics Workbook, so they have been "field-tested," but not within the WRTR curriculum. I see no reason whatsoever, however, why there would be any difficulty in doing so, and, in fact, believe they would make it much easier to explain the coding of many words.
The last page of this section, Survey of the Ayres List, relates the order of introduction of the phonograms to the order they first occur in specific words in the Ayres List found in the Fifth Edition of WRTR.