Possible consonant clusters.

One of the most widely invoked arguments of this nature regards the rules for possible consonant clusters, which reflect the fact that sequences of segments have to be organized into definable syllables, and languages impose various restrictions on how syllables can be formed. We will start with possible word-beginnings and word-ends in English, and see how these relate to syllable structure. Initial clusters may have the form sC (C¼consonant), as in stick, spit, skunk, also snow, smite, slay, or they may be of the type OR (O¼obstruent, R¼glide or liquid) as in fray, through, fly, bleed, breed, pray, clue. The longest possible initial cluster has the shape sCR (sprint, sklerotic, strip, splice), which reflects the interaction of the two rules pertaining to possible initial consonant clusters.

Words which violate these rules cannot be words of English, thus consonant plus stop clusters other than sC are nonexistent and are judged by native speakers as being impossible (*bnick, *pnort, *ptack, *dbonk, *fnilge). Likewise there are no stop+fricative clusters (*kfimp, *ksunk, *pthing). Sonorants as the first member of a cluster are also excluded: *mbop, *rtot, *lfay, *yluck, *wnurge. There are additional, more specific restrictions on the pattern of allowed initial clusters. For example, coronal plus l is excluded (*tluth, *dlifficult, *thlash, *chlort), except for [sl] (sleep) thanks to the special rule allowing sC clusters. Sequences of labial+w are also disallowed (*pwang, *bwint, *mwerge, *fwet).

Clusters of consonants at the end of English words are also subject to restrictions. Any consonant except h can stand at the end. Consonant clusters can be of the form sonorant+consonant. Thus, words can end with glide+consonant (height, clown, mouse, leaf), liquid plus consonant (halt, harp, hart, bilk, false, film, born, farm, carl), or nasal+consonant (dance, runt, punk, brand, lamp, lymph, lense). There are certain restrictions on such final clusters. One is that in a nasal plus voiced stop cluster, the stop must be noncoronal, thus fringe, hand are allowed and *[læmb], *[hæŋg] with pronounced final [b], [g] are disallowed. The consonants [r j w] cannot be the second consonant in a cluster; [l] can follow [r j w] but not a nasal, and nasals can only follow [r j w l].

Certain sequences of voiceless obstruents are also allowed, as long as either the second consonant is [+anterior, +coronal] (apt, act, depth, apse,

raft), or else the first consonant is /s/ (cast, cask, clasp). Obstruent sequences ending in a noncoronal or nonanterior consonant are excluded (*atp, *atc, *lupsh, *ratf), as are clusters of fricative+obstruent where the fricative is not s (*cashk, *lithp,*rafk). Clusters ending with voiced obstruents are also disallowed (*abd, *abz). Notice that all of these rules involve allowed or disallowed sequences of two consonants – no rules of combination specifically apply to just three-member clusters or four-member clusters, and observed limits on initial and final clusters all reduce to a chain of limits on two-consonant sequences. It is also important to note that certain otherwise excluded clusters do arise when inflectional affixes are added; for example the final cluster [bz] exists in the plural cabs and [gd] exists in past tense flagged, but such clusters only exist as combinatins of root plus suffix.

The importance of the syllable in understanding these restrictions comes from the fact that these are not just restrictions on how words can begin or end, they are restrictions on how syllables can begin and end. Taken together, the preceding rules for syllable beginnings and endings define possible word-medial clusters. Some examples of allowed word-medial clusters are [tm] in atmosphere, [mb] in camber, [ʃr] in mushroom, [rt] in barter, [sb] in asbestos, [bn] in Abney, [md] in Camden, [db] in Ledbetter, [ʃk] in ashcan, and [kf] in breakfast. Note that these are not possible initial or final clusters, except that [rt] is a possible final cluster. In such cases, the first consonant is the final consonant of one syllable, and the second is the initial consonant of the next syllable – [kæm.br̩ ], [bar.tr̩ ], [æb.nij], [lɛd. bɛ.tr̩ ], [brɛk.fʌst]. Three-consonant clusters are possible, for example bolster, Andrew, hamster, translate, electron, costly, which can be arranged into a possible syllable-final sequence followed by a possible sylable-initial sequence, viz. [bol.str̩ ], [æn.druw], [hæm.str̩ ], [træn.slejt], [ʌ.lɛk.tran], [kast.lij].

Now consider illicit three-consonant medial clusters, exemplified by *catmbop (*[tmb]), *fishrtot *[ʃrt], *gasbnick (*[sbn]), *lamdbonk (*[mdb]), *gushk-fimp (*[ʃkf]). We have seen that the individual consonant pairs are possible – [tm], [mb], [ʃr], [rt], [sb], [bn], [md], [db], [ʃk], and [kf] – but only because the first member is a syllable-final consonant and the second is syllable-initial. The three-consonant cluster *[tmb] is ruled out because tm is not a possible syllable-final cluster and mb is not a possible syllable-initial cluster, thus m cannot be assigned to any syllable – neither cat.mbop nor catm.bop follows the rules for syllabification of consonants in English. Similarly, sb is not a possible syllable-final cluster and bn is not a possible initial cluster, thus the cluster in *gasbnick cannot be syllabified. A syllable-based analysis of possible clusters automatically predicts the restrictions on word-medial three-consonant clusters. Without the syllable as an organizing unit over segments, a very complex set of additional rules would be required to account for the restrictions on medial clusters