Double consonants in English: Graphemic, morphological, prosodic and etymological determinants

b. , ,
, ,
,
, ,

Likewise, Brame (1983b) points to the fact that the letter names for , , and are , , and respectively, as opposed to /* and /* for example. There is thus no opposition in this context. This does not explain word-final consonant doubling for /, , , and – but it makes it look a little less haphazard.

2.: Moreover, the vowel letters preceding word final double consonants in (3b) do not always correspond to short vowel phonemes; this holds for , , and similar words (cf. Carney 1994: 124f.)⁷. This again sets the group , , apart from other consonant letters.

These are the graphotactic constraints on consonant doubling in English: Not all consonant letters occur as geminates. Double consonants occur after a single vowel letter and before one or more vowel letters. There are some well-defined exceptions to these constraints. They hold across both morphologically simple and morphologically complex words.

3. The core: morphologically complex words

Consonant doubling regularly occurs at morpheme boundaries. The following requirements hold (cf. e.g. Cummings 1985: 161ff.):

(5) Consonant doubling occurs before a suffix with an initial vowel letter if a) there is a single base-final consonant letter from the set in (1) before the boundary and b) this consonant letter is preceded by a single vowel letter.

This regularity is purely graphemic. It captures almost all double consonants in inflectional products (like ,

, ) and most of the derivational ones (like ,
, ). As noted above, the statement refers to the graphemic structure of the base. This explains spellings like the following, which would be hard to motivate from a phonographic perspective:

(6) a. –

b. –
c. –

In (6a), final is dropped because the suffix begins with a vowel (see below). This leads to a potentially misleading correspondence for (cf. , ), but consonant doubling does not occur because the requirement (5) holds (in the base word, the is not graphotactically final). Likewise, in (6b) the consonant is not doubled because there is more than one preceding vowel letter (). In (6c), although the in the suffix is silent, it still triggers doubling of the preceding consonant letter because -ed is a suffix with an initial vowel letter.

What is the reason for this reference to base forms, which leads to deviations from (more or less) regular phonographic correspondences? The systematic reason for consonant doubling can be found in -deletion before suffixes with initial vowel letters like <-ing>, <-er>, <-ance> etc. For example, Carney (1994: 129) and Palmer et al. (2002: 1577) observe that while in monomorphemic words the differences in the corresponding vowel qualities are expressed by the presence or absence of final (e.g. – ), in morphologically complex forms (with vowel-letter-initial suffixes), the same difference is expressed by the presence or absence of a double consonant (e.g. – ). Carney (1994: 129) adds that a constant marking of long or diphthongic correspondences by silent (even in morphologically complex words) would lead to spellings with vowel letter clusters , like * and *. Carney supposes that this spelling is not an option because it would interfere with the correspondences these clusters have in monomorphemic words (cf. ,
).

While that is certainly true, it is possible to go further. The second syllable in *, for example, could potentially be interpreted as stressed and long (cf. , , ). The framework of Evertz & Primus (2013) offers a suitable explanation for this: graphemic syllables with complex vowel letters are ‘heavy’, and they regularly correspond to stressed phonological syllables.

The need to mark short vowels in morphologically complex forms thus follows from the impossibility to retain final before vowel-letter-initial suffixes. If the argument sketched above is correct, we would expect final and consonant doubling in essentially the same positions. For final , there are two major constraints: It does not occur after complex vowel letters (7a), and it rarely occurs after consonant letter clusters (7b) (cf. Venezky 1999: 48):

(7) a. , *; , *

b. , *; , *

As noted above in (5), consonant doubling at morpheme boundaries follows exactly these two constraints: there is no doubling after a complex vowel letter (8a) or after another consonant letter (8b).

(8) a. , *; , *
b. , *; , *

Consonant doubling is thus subject to the same constraints as final is. This is further evidence for the close relation of both markers. Moreover, when words with final and consonant-initial suffixes are combined, the is not dropped (cf. – , *), and accordingly stem-final consonants are not doubled either (cf. – , *). Consonant doubling thus seems like a backup solution: Whenever final is not available in a morphological process, consonant doubling helps out.

Summing up, double consonants are motivated by the need to mark vowel quality in morphologically complex words with vowel-initial suffixes. This need in turn arises because final cannot be employed for reasons of graphemic syllable weight. As a consequence, morphologically complex words are formed very regularly on the graphemic form of the respective base. This may lead to deviating correspondences in the morphologically complex form. In the following, I will examine both inflectional (3.1) and derivational (3.2) cases in more detail.

3.1 Inflection

If an inflectional suffix (except -s) operates on a monosyllabic basis, statement (5) is exceptionless. This leads to forms like the following:

(9) begged, banned⁸, fatter, starred, thinnest

The reference to the graphemic form of the base also serves to explain why some spellings are excluded for irregular past tense forms like kept and slept: Phonographically, * and * should be possible (cf. e.g.

), but the fact that there is no base and prevents these spellings.

For polysyllabic bases, there are numerous exceptions, however:

(10) visiting/*visitting, authored/*authorred

There are two ways to deal with these exceptions. The data in (10) can be straightforwardly explained by hypothesis (11), which I will call the prosodic hypothesis and which is an additional requirement to (5) above:

(11) Consonant doubling occurs if the base-final syllable receives phonological stress.

The bases in (10) and many others are trochees with unstressed ultimates, and accordingly the base-final consonants should not be doubled. On the other hand, for iambic bases – i.e. bisyllabic bases with an unstressed syllable followed by a stressed syllable – (11) correctly predicts consonant doubling:

(12) , , ,

Cases like

and
are prima facie counterexamples – the consonant is doubled even though the base-final syllable is unstressed. But as e.g. Venezky (1999: 83) and Carney (1994: 223) have pointed out, this is a very special case: Without consonant doubling, the stem-final in *
would be wrongly assumed to correspond to [s]. Thus, can be motivated here by the pursuit of phonographic consistency.

However, compounds (and pseudo-compounds) are not covered by the prosodic hypothesis:

(13) /*, /*, /*

The words in (13) should not have a double consonant according to the prosodic hypothesis because the base-final syllable is unstressed. One could advocate that in these cases the stem-final syllables bear secondary stress (cf. Cummings 1988: 165). But it is far from clear that the second syllables in sandbag, babysit and airdrop are intonationally categorically different from those in visit and author. The difference might just lie in the full vs. reduced vowel quality (Bolinger 1986:. 351 N.3; 1989: 215f.; Fudge 1984: 31)⁹. The intonational difference between e.g. outfit vs. trumpet seems to be a matter of degree and personal preference.

An alternative way to capture the data in (13) is (14), which I will call the morphological hypothesis:

(14) Consonant doubling occurs if the base-final graphemic syllable is a monosyllabic root.

This easily captures cases like sandbag, babysit, airdrop. Cases like /* and /* are also covered by the morphological hypothesis (no base-final monosyllabic root → no consonant doubling), as well as cases like , , , and (base-final monosyllabic root → consonant doubling). But the morphological hypothesis also explains cases with a varying degree of transparency from words like kidnap, bootleg, handicap to completely opaque forms like humbug, zigzag, hobnob (which all occur dominantly with doubled consonants), and variation in cases like /, /, /. Variation hinges on the morphological analysis: If a writer analyses -ship in worship as a root, the consonant is doubled, if worship is monomorphemic for her, it remains the way it is. If a writer analyzes com- and for- in combat and format as prefixes and thus -bat and -mat as roots, the consonants are doubled; otherwise, they remain single consonants.

The prosodic hypothesis has problems with these data – at least in its prosodic formulation with reference to secondary stress. A possible reformulation could be in terms of vowel quality: after all, this is a respect in which compounds like sandbag, bootleg and kidnap differ from polysyllabic roots like summer, orbit or blanket. Ultimately, however, this difference could also be argued to be morphological. Only vowels in affixes and in non-initial syllables of polysyllabic roots are reduced, so the full vowel in the final syllable in sandbag, babysit, and airdrop indicates some sort of lexical content. Both phonology (in form of vowel quality) and graphemics (in form of consonant doubling/non-doubling) thus operate on similar kinds of morphological information.

But why are consonants doubled only in monosyllabic roots? This may have to do with the distribution of -deletion and the functional need to mark vowel quality. There are 121 pairs of phonologically monosyllabic words which only differ in the presence or absence of final (e.g. – , – , – ). Consonant doubling is necessary in these cases to prevent systematic homography of morphologically complex forms (e.g. , , ). For phonologically bisyllabic words, there are only 12 such pairs, and almost all involve semantically closely related words (e.g. – , – ,