From the archives...
The following question was originally posted on the (now discontinued) LOE Forum.
We went over the rule today as to when aw is used to make the third sound of A. The word "awful" does not follow any of the stated reasons as to when to use aw. Page 95 [of Essentials 1st Edition] notes that this phonogram is "most commonly used at the end of a base word, before an N and before an L." Can anyone tell me?
The phonogram AW may actually be used anywhere. The only "rule" for this phonogram is simply that it "MAY be used at the end of English words," in order to distinguish it from AU, which may not. The rule is not restricting the use of AW.
So the "most commonly" in the lesson you were reading is important - it intentionally doesn't exclude other uses, but rather offers a description of where AW most frequently occurs in order to help students make good educated guesses. We've worded the lesson very carefully!
Those are the places where AW is most commonly used. To help students remember spellings more easily and help them make good educated guesses when spelling an unfamiliar word, it's beneficial to point out patterns like this. However, that does not mean that words that are outside this "most common" tendency are exceptions. It doesn't violate any spelling rules when AW is used somewhere else (such as in crawl dawdle gawk hawk).
With the word awful specifically, your best tool for helping your student remember the spelling is morphology: looking at the root and discussing the connection to "awe" and "awesome." However, when you are teaching this word to students, keep in mind that they won't be able to know for sure which of the permitted spellings is correct until you tell them, so you will need to provide a phonogram cue as they write the word. This is true any time students are learning to spell a word with a sound that can be spelled in more than one way.