“Fizzle/Floss Rule”

Does Sammy really like fried zebras? 

The pattern of doubling <f>, <l>, <s>, and <z> in a one-syllable word after a short vowel, sometimes referred to as the “Floss” or “Fizzle” rule, has a few people still puzzled. For the heck of it, I asked AI about it. In addition to various renditions of the pattern, I was told this rule also applied to the doubling rule for adding suffixes. This couldn’t be further from the truth! Be careful about what you read and who your source is before you accept it as true. As I continued Googling, in addition to referring to this pattern as the “Floss Rule” and the “Fizzle Rule,” I saw that some programs are now calling this doubling of the final consonant the “Sammy Rule.”

Why so many names? 

I am unsure who coined the phrase “Floss Rule,” but I do know it was not Anna Gillingham! The term floss rule did not appear until the rewriting of her manual in 1997 by people other than herself. In the 1960 version, page 152, it is simply called Rule 1, Words ending in ff, ll, ss. It also includes wisdom no longer mentioned in the current rendition.  


I then wondered about the term “Fizzle Rule.” I dug out my collection of old Orton Gillingham training manuals and other phonics-based materials and didn’t see it appearing until 1997 in the Sonday System Learning Plan book. Before the printing of the SS, Arlene Sonday’s, “Watermelon Manual,” a book used initially for OG training by Orton Gillingham of Minnesota,  didn’t include the term “Fizzle.” Curious, I reached out to Arlene, asking her if she knew who coined the phrase. She was unsure; she said she liked the way it sounded. So, the mystery remains. With the addition of the “Fizzle Rule,” the “Floss Rule” was expanded to include <zz>. 

So let’s try to demystify the pattern of doubling <f>, <l>, <s>, and <z> in a one-syllable word after a short vowel. I will only be discussing one-syllable words in this conversation. If you are interested in double medial letters, check out this blog post. If you are wondering about doubling final consonants when adding suffixes, go here

Historically, the doubling of the final consonant after a short vowel came into use in Middle English to distinguish long and short vowels in one-syllable words.

Facts About Double <f>

  • <f> is doubled in free bases* in the final word position
  • Holdouts to doubling  <f> include clef and chef,  both words adopted from French.  
  •  if  is a native English word. Interestingly, from the 13th to the 17th century, if  was spelled iff, marking the devoicing of <f> (/v/ is the voiced partner to /f/ ). It is important to note in Old English, <f> spelled both /f/ and /v/.
  • The word of  is neither doubled nor spoken as /f/, following the old English demarcation of voiced <f>.
  • Lastly, the final group of holdouts include words with a fossil <e> meaning <e> is no longer spoken as it once was. These words include gaffe and giraffe.

Facts About Double <s>

  • Before talking about /s/ and /z/, it is essential to remember that <s> carried the sound for both spellings for quite a while in early English before <z> was added back to the alphabet. Read more about that here
  • <ss> is used after a stressed short vowel to avoid ending a free base* in a single <s>.  
  • Holdouts to this pattern include
    •  Words that are shortened from other words, such as gas-gasoline, bus-omnibus, sis-sister 
    • The function words this, has, his
    •  is, and as, also function words, follow the “Short Word Rule” (meaning words that carry content will contain three or more letters); additionally, double <s> will not be pronounced /z/.  
    • Words such as “yes” carry their own historical reasonings. 

Facts About Double <l>

  • <l> is doubled in free bases* in the final word position.
  •  Holdouts include but are not limited to, nil, mil, el, gel, Hal.
  • While <all> is a short vowel, it is not the expected vowel sound; instead, <all> will be pronounced /ŏl/ due to a change in pronunciation in the 15th century. The only holdout is shall with a final <all> as /ăl/. However, when a (monosyllabic) word ends in <al>, it will be pronounced /ăl/, such as Cal.  So, I suggest we expose our students to this pattern when teaching short <a> CVC instead of calling these words exceptions. 
  • This pattern also applies <oll> as /ōl/ in words such as troll, <oll> as in doll is the only word we have that uses short <o>, as in other words, there is a tendency to pronounce <o> as a long vowel before <l>, e.g., bolt, old and folk. The word doll” strangely enough, comes from the word Dorothy. 
  • Although we are focusing on one-syllable words, it is essential to point out that the freebases will remain doubled when adding prefixes, as in resell and appall. 

Facts About Double <z>

  • Because of the close relationship to <s>,  <z> tends to follow the same constraints as <s>. An example of a constraint is ending a free base in a single <s>; instead, we would double <z> after a short stressed vowel in the final word position.  e.g. buzz versus buz.
  • We will find double <z> after a stressed short vowel about 50 percent of the time; other times, we will see a single <z> in words such as whiz and fez. Since this is such an equal division, I don’t tend to think of these words as holdouts. I teach the doubling pattern words and touch on the other words as needed. 

 At the end of a one-syllable word after a short, stressed vowel, we double <f>,<s>,<z>, and <l>. I tend to say, “After a short vowel, we double <f>, <s>, <z>, and <l>.”  Why do I leave the rest off? Because, at this point, all my student is working with is a one-syllable word. I don’t want to tax the cognitive load with more information than they need. Further along the continuum with two-syllable words, we will have a different discussion. This will involve closed syllables and the introduction of roots such as gress, as well as suffixes such as ful, ness, and less

 It is imperative that we know our students understand the vocabulary we use. Because this is the first rule-based pattern I teach my students, I need to know they know what I am talking about! 

  • Do they know “after,” or maybe you say “followed by,” more complex verbiage? 
  • Does your student know what it means to “double” something?
  • Can they give you an example of a consonant?
  • And most importantly, do they know what a short vowel is? Can they identify the short vowel sound when you are doing the sound pack review?

Never assume anything. Years ago, I encountered an older student who had no idea what I was talking about when I said “followed by.” Since then, I have seldom used that term. I even show my students a string of patterns (such as a line of colored pens) and ask what comes after what. This may seem like overkill, but believe me, this quick activity proves that my students will understand me. 

How do I teach this pattern? Like all introductions to new material, it is student- or group-specific. I can only introduce one letter at a time with some students, while I can teach them all with others. So, after I am sure we are all on the same page regarding verbiage, these are the steps I follow to teach this pattern:

  • I will show the student the grapheme card. Let’s use <f> as an example. I say. “ After a short vowel, we double <f>, “ and they write two <f>s and say /f/. 
  • They then read a list of words with final <ff>
  • I dictate words containing <ff>. 
  • I will then include this pattern in my contextual reading and game time

Repeat accordingly with the other letters or wait until another lesson, if necessary. This new material will appear in all aspects of my next lesson. 

Some people like the mnemonic “Sammy Likes Fried Zebras” or other sentences. Personally, I don’t; I tend to limit oral clutter. I also see people wanting their students to write this sentence, which I find odd since the student has worked only with CVC short vowel words up to this point. 

Before I end this post, I want to add a few final notes on the pattern that wasn’t addressed earlier. Words like ebb and odd are doubled because of the Short Word Rule discussed earlier. Inn is doubled to avoid confusion with the word in and the Short Word rule. Putt is distinguished from put with the additional <t>. For those of you who have a student who wants to know more,  I have a list of these exceptions to the rule in my wordbook Words.  The answer to these types of words is always in the word's etymology. When in doubt, do your research! 

I would love to hear about your experiences with the “Floss/Fizzle Rule”! Please share in the comments below.

Happy fizzling and flossing!  

*a free base is a word that can stand alone


American English Spelling, D.W. Cummings

The American Way of Spelling, The Structure and Origins of American English Orthography,  Venezky

Remedial Training for Children with Specific Disability in Reading, Spelling, and Penmanship Anna Gillingham and Bessie Stillman ©1960 

The Gillingham Manual  ©1997 

Sonday System Lesson Plan Book, Arlene Sonday ©1997 

The Orton Gillingham Approach to Teaching Reading Writing and Spelling, Arlene Sonday ©1994 (the “Watermelon Manual”)

Next article -ch or -tch, which witch?

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