The entire list of words to which this ‘rule’ applies is add, all, ass, ebb, egg, ell, ill, inn, odd, off (contrast the function words as, in, of), and the name Ann, and within this list the doubling in all, ass, ell, ill, off is regular anyway.
In terms of spelling, this rule also applies to err (contrast the filler word er) even though its pronunciation is a single long vowel and contains no consonant (in RP). In all, however, where consonant-doubling is concerned, this rule seems to apply only to the 12 three-letter words just listed.
Exceptions: ad (advert(isement)), el, em, en (old-fashioned printers’
terms for sizes of spaces), id.
This is part of a general tendency in English that content words must be spelt with at least three letters, even if they contain only one or two phonemes and therefore could be spelt with fewer than three letters. Other examples are:
How do you know when to write a consonant letter double? 117
• (one-phoneme words) awe, aye, eye, ore, owe (contrast the function words I, oh, or)
• (two-phoneme words) bee, buy, bye, hie, high, hoe, low, know, sew, sow, wee (contrast the function words be, by, Hi!, ho (exclamation of surprise), lo, no, so, we), plus ate pronounced /et/, bow, car (cf. the vehicle name Ka), chi (and this Greek letter name does indeed have the alternative spelling ki), die, doe (but the spelling do is pre-empted), dough, dye, ewe, far, fee, feo, fie, foe (contrast Fo, as in Fee, Fie, ..., Fum – but is Fo a word?), guy, joe, key, knee, lea, lee, lie, lye, mow, nigh, pea, pee, pie, poh, quay, roe, row, sea, see, sigh, tea, tee, toe (but the spelling to is pre-empted), tow, rue, rye, vie, whoa, woe, yew.
Some of the positional spelling constraints of English help to maintain the three-letter rule. For example, if it were generally acceptable to spell word-final /ʤ/ with <j> then edge could be spelt *ej. This spelling would observe the rule against doubling <j>; *ejj would be an even odder spelling (the <jj> in hajj, now the accepted spelling of the word for the Muslim pilgrimage, reflects the doubled pronunciation of the final consonant in Arabic). Some of the common digraphs also help to maintain the three-letter rule; for example, ash would consist of two letters if English had a one-letter grapheme for /∫/.
Three-phoneme content words containing /ks/ are mostly written with two letters, using <x>; ax (in US spelling; contrast British axe), ex (contrast the river-name Exe), ox and the Greek letter name xi. However, the examples just cited appear to be the only 3-phoneme words in the language containing the sequence /ks/. There are about 15 three-phoneme words containing /juː/, which can be spelt <u>, and these words could therefore also in theory be written with two letters. However, only the Greek letter names mu and nu are written this way, and all the rest are written with at least three letters: cue, dew, due, few, hew, hue, lieu, mew (homophone of mu), gnu, knew, new (these last three being homophones of nu), pew, queue, view. And neither ewe nor you would ever be written *u or *yu (cep
wen txtng, fcors).
Other function words spelt with fewer than three letters are a, ah, am, an, as, at, er, he, I, if, in, is, it, me, my, of, on, so, to, up, us, we, ye. Do and go, despite often being content words, make do with two letters because of their other use as auxiliary verbs; in contrast, the function word are has three letters even though it could be spelt ar like the filler word (but this would make the contracted forms *they’r,*we’r,*you’r look very odd).
Other content words which are spelt with two letters (and are therefore exceptions to the three-letter rule) are ma, pa, pi (the Greek letter name and numerical constant; contrast pie), ta (‘thanks’; contrast tar), and the musical terms do, re, mi, fa, so, la, ti.
4.3.3 Consonant phonemes /b d f g k p t z/ are almost always spelt with double letters before final /əl/ spelt <-le> where the immediately preceding vowel phoneme is short, stressed and spelt with a single letter
Examples:
babble, dabble, gabble, rabble, scrabble, pebble, dibble, dribble, nibble, scribble, bobble, cobble, gobble, hobble, nobble, wobble, bubble, rubble, stubble;
addle, skedaddle, paddle, saddle, staddle, straddle, swaddle, twaddle, waddle, meddle, peddle, Biddle, diddle, fiddle, griddle, middle, piddle, riddle, twiddle, widdle, coddle, doddle, noddle, toddle, cuddle, (be)fuddle, huddle, muddle, puddle;
baffle, raffle, snaffle, waffle, piffle, riffle, skiffle, sniffle, whiffle, duffle, kerfuffle, muffle, ruffle, scuffle, shuffle, snuffle, truffle;
(be)draggle, gaggle, haggle, raggle-taggle, snaggle, straggle, waggle, giggle, jiggle, niggle, wiggle, wriggle, boggle, boondoggle, goggle, hornswoggle, joggle, toggle, woggle, juggle, muggle, smuggle, snuggle, struggle;
cackle, crackle, hackle,(ram)shackle, tackle; freckle, heckle, speckle; fickle, mickle, pickle, prickle, sickle, stickle, tickle, trickle; cockle; buckle, chuckle, knuckle, muckle, suckle, truckle;
apple, dapple, grapple, cripple, nipple, ripple, stipple, tipple, topple, supple; (em)battle, cattle, prattle, rattle, tattle, wattle, fettle, kettle, mettle, nettle, settle, brittle, little, skittle, spittle, tittle, whittle, bottle, dottle, mottle, pottle, throttle, cuttlefish, scuttle, shuttle, Suttle;
(be)dazzle, frazzle, razzle-dazzle, embezzle, drizzle, fizzle, frizzle, grizzle, mizzle, sizzle, swizzle, nozzle, s(c)hemozzle, schnozzle, guzzle, muzzle, nuzzle, puzzle.
Also squabble, quibble, squiggle if the <u> in these words is counted (as it should be) as a consonant letter.
Most of the words in this list belong to the less formal/more Anglo-Saxon part of the vocabulary. This rule is one of the only two situations in
How do you know when to write a consonant letter double? 119 which <zz> is the regular spelling of /z/, since /z/ is never spelt <s, ss, z>
in this position.
Exceptions: chattel, subtle, treble, triple (if these words followed this rule they would be spelt *chattle,*suttle,*trebble,*tripple – and, as shown above, there is a surname spelt Suttle).
Extensions (1): Where the consonant between the vowel and <-le> is /s/ it is mainly spelt <st> (see section 3.7.6): nestle, pestle, trestle, wrestle; bristle, epistle, gristle, mistle thrush (also spelt missel thrush), thistle, Thistlethwaite, Twistleton, whistle; apostle, jostle, Postlethwaite, throstle;
bustle, hustle, rustle. This extension also applies to mistletoe even though the <-le> is not word-final. Sub-exceptions: hassle (but I once received an email with this word spelt *hastle, showing the power of the <st> sub-rule), tussle which conform to the main rule above, plus muscle, which conforms to neither the main rule nor this sub-rule about medial /s/ (nor does corpuscle,but since it is stressed on the first syllable it does not fall under the main rule), and missel thrush in that spelling.
Extensions (2): There are also a few words where the other conditions are met (consonant preceding final /əl/ not in the set /l, m, n, r/ or in the set which never double, vowel preceding that stressed, short and spelt with one letter) but the final /əl/ is not spelt <-le> which nevertheless have the consonant spelt double: chattel, cudgel, duffel, estoppel, fossil, glottal, jackal, missal, missel thrush in that spelling, mussel, nickel, offal, rebuttal, satchel, tassel, vassal, vessel, wittol and a few words in <-ittal>
which are derived forms obeying the main consonant-doubling rule:
(ac)quittal, committal, remittal. This list contains the only words, apparently, in the entire language with final /əl/preceded by /ʤ, ʧ/ spelt double as
<dg, tch>: cudgel, satchel.
There are no words following this pattern in which the consonant phoneme before the /əl/is /m, n, r/, that is, none spelt <*-mmle, *-nnle, *-rrle> (for a possible reason see the end of section 4.4.3) – contrast mammal, pommel, pummel, trammel; channel, flannel, fennel, kennel, funnel, runnel, tunnel; barrel, sorrel; also quarrel, squirrel if the <u> in these words too is counted as a consonant letter. Also, it would be odd if the consonant phoneme before the /əl/ were /l/ - the only word with a short, stressed vowel followed by /l/ followed by /əl/ appears to be the obsolete word fallal (‘trinket’). And by definition this rule cannot apply to <h, j, q, v, w, x, y> even though, for example, axle, hovel could in theory be spelt *axxle, *hovvle.
For the converse of this rule, see sections 4.4.2-3 below.
The sets of consonant phonemes to which this rule does or does not apply cut across those which are mainly written double or single at the end of one-syllable words after a short vowel spelt with one letter – see Table 4.2.
TABLE 4.2: NON-EQUIVALENCE OF SETS OF CONSONANT PHONEMES SPELT DOUBLE IN TWO SITUATIONS
Consonant phonemes which are mainly written double at the end of one-syllable words after a short vowel spelt with one letter
Consonant phonemes which are mainly written single at the end of one-syllable words after a short vowel spelt with one letter Consonant phonemes which are
mainly written double between a stressed short vowel spelt with one letter and word-final /əl/ spelt <-le>
/k f s* z/ /b d g p t/
Consonant phonemes to which
the rule above does not apply /ʧ ʤ l v/ /m n/
*/s/ is mainly spelt <ss> word-finally and <st> medially in these circumstances.
Consonant phonemes to which both rules are irrelevant: /h r w j/ because they do not occur word-finally, and /ŋ ∫ ʒ θ ð/ because they have no one-letter word-final spelling.