Clusters, Digraph, Blends, and Diphthongs

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Clusters of either consonants or vowels add to the challenge of beginning reading learner. Sometimes the clustered letters each make a sound, in which case early readers can apply phonetic decoding strategies to read them. However, other combinations make new or unexpected sounds that must be actively taught separately. Many reading specialists recommend that these more complicated sound patterns be taught after student demonstrate solid phonetic decoding skills.

Consonant Digraphs

Consonant digraphs are clusters of consonants pronounced as a single sound. There are seven basic consonant digraphs; ch, ck, th, sh, ph, ng, wh. However, "ch" has three pronunciations, "ch" as in chin, "k" as in chorus, and "sh" as in chute, and "th" is pronounced with active voicing as in the or without as in thank. These discrepancies are often challenging for early readers, especially if they are also English language learners, because the sounds often resemble other letters. For example, "ph" combines to sound like [f]. Three additional digraphs occur regularly in English, "wr," "gn" and "kn." These are referred to as "ghost digraphs because the initial letter used to make a sound but no longer does.

Consonant Digraphs

ch, which makes the /tʃ/ sound as in watch, chick, chimpanzee, and champion
ck, which makes the /k/ sound as in chick
ff, which makes the /f/ sound as in cliff
gh, which makes the /g/ sound as in ghost and ghastly
gn, which makes the /n/ sound as in gnome and gnarled
kn, which makes the /n/ sound as in knife and knight
ll, which makes the /l/ sound as in wall
lm, which makes the /m/ sound as in palm and calm
mb, which makes the /m/ sound as in lamb and thumb
ng, which makes the /ŋ/ sound as in fang, boomerang, and fingerprint
ng, which makes the /nʤ/ sound as lounge
nk, which makes the /ŋk/ sound as in ink, sink and rink
ph, which makes the /f/ sound as in digraph, phone, and phonics
qu, which makes the /kw/ sound as in quick
sh, which makes the /ʃ/ sound as in shore, shipwreck, shark, and shield
ss, which makes the /s/ sound as in floss
ss, which makes the /ʃ/ sound as in pressure and mission
th, which makes the /θ/ sound as in athlete, bathtub, thin, and thunderstorm
th, which makes the /ð/ sound as in this, there, and that
wh, which makes the /w/ sound as in where and which
wr, which makes the /r/ sound as in write
zz, which makes the /z/ sound as in fuzz and buzz

Consonant Trigraphs

chr, which makes the /kr/ sound as in chrome and chromosome
dge, which makes the /ʤ/ sound as in dodge and partridge
tch, which makes the /tʃ/ sound as in catch, match

Consonant Blends

Blends are consonant pairs in which each consonant makes its own sound. For example, if you listen carefully, you can hear the "b" and the "l" in blue. There are many blends in the English language. They are most often categorized into r-blends, such as "br" and "cr", s-blends, such as "sc" and "sk" and l-blends, such as "bl" and "cl." Blends are not usually a significant challenge for beginning readers. Reading blends uses a decoding strategy called blending that students are already using.

Two-Letter Blends

bl, which make the /bl/ sound as in blend and blight
br, which make the /br/ sound as in break and brown
cl, which make the /cl/ sound as in cluster and class
cr, which make the /cr/ sound as in crash and cross
dr, which make the /dr/ sound as in drive and drab
fl, which make the /fl/ sound as in flu and flake
fr, which make the /fr/ sound as in freedom and frost
gl, which make the /gl/ sound as in glad and glory
gr, which make the /gr/ sound as in green and gravy
nd, which make the /nd/ sound as in blend and send
pl, which make the /pl/ sound as in play and plow
pr, which make the /pr/ sound as in prime and prowl
sl, which make the /sl/ sound as in slogan and sloppy
sm, which make the /sm/ sound as in small and smart
sn, which make the /sn/ sound as in snail and snore
sp, which make the /sp/ sound as in special and spackel
st, which make the /st/ sound as in stop and start

Three-Letter Blends

shr, which make the /ʃr/ sound as in shroud
spl, which make the /spl/ sound as in splash and splendid
spr, which make the /spr/ sound as in spring and spray
squ, which make the /sqw/ sound as in squid and squelch
str, which make the /str/ sound as in struggle and strap
thr, which make the /θr/ sound as in throw

Vowel Digraphs

Vowel digraphs are pairs of vowels that make one sound. The first ones taught are usually those in which the initial vowel makes its long sound and the second is silent. For example, "e" is short (ĕ) when it's by itself in men and long (ē) when it's combined with "a" in mean. The vowel digraph rule is frequently taught in schools with the saying "when two vowels go a walking, the first one does the talking." However, as with consonant digraphs, there are exceptions. For example, the "oo" in "book" is not pronounced [oh]. Despite this, vowel digraphs are usually less challenging for beginning readers than consonant digraphs.

Vowel Diagraphs

ai, which usually make the /eɪ/ sound as in aim, rain, braid, paint, tail, twain
au, which usually make the /ɑ:/ sound as in fault, gaunt, fraud, launch, paus
aw, which usually make the /ɑ:/ sound as in saw, paw, claw, dawn, and crawl
ay, which usually make the /eɪ/ sound as in ray, say, stay, day, say, play, spray
ea, which usually make the /i:/ sound as in eat, sea, eeah, leaf, peach, mean
ea, which usually make the /ɛ/ sound as in dead, heea, spread, health, meant
ea, which more rarely make the /eɪ/ sound as in break, great, steak, yea
ee, which usually make the /i:/ sound as in peek, see, queen, sleep, cheese
ei, which usually make the /eɪ/ sound as in veil, beige
ei, which usually make the /i:/ after [s] sounds as in seize, receipt
eo, which usually make the /i:/ sound as in people
eu, which usually make the /ju:/ or /u:/ sound as in sleuth, deuce
ew, which usually make the /ju:/ or /u:/ sound as in few, new, shrewd
ey, which usually make the /i:/ sound as in key, money, valley
ey, which usually make the /eɪ/ sound as in they, whey
ie, which usually make the /i:/ sound as in brief, field, grieve, piece
oa, which usually make the /oʊ/ sound as in oat, loam, groan, loathe, loaves
oe, which usually make the /oʊ/ sound as in doe, hoe
oo, which usually make the /u:/ sound as in boo, food, smooth, moose
oo, which usually make the /ʊ/ sound as in book, look, good, and stood
ou, which more rarely make the /u:/ sounds as in you, soup, group, rouge
ow, which usually make the /aʊ/ sounds as in how, down, browse
ue, which usually make the /u:/ sound as in due, rue, sue, blue, clue, flue
ui, which usually make the /u:/ sound as in suit, fruit, cruise, juice, sluice

Vowel & Consonant Combination Trigraphs

augh, which usually make the /ɑ:/ sound as in caught, taught, daughter
al+consonant, which usually make the /ɑ:/ sound as in talk, hall, scald, salt
wa, which usually make the /wɑ:/ sound as in want, wash, swamp
wa, which usually make the /wæ/ sound as in wax, wag, swam
ua, which usually make the /wæ/ sound as in quack
eigh, which usually make the /eɪ/ sound as in eight, weigh
o+ll, which usually make the /ɑ:/ sound as in doll, loll
o+st, which usually make the /ɑ:/ sound as in cost, lost, frost
ou+l, which usually make the /oʊ/ sound as in soul, poultry
o+ld, which usually make the /oʊ/ sound as in gold, scold, fold
o+lk, which usually make the /oʊ/ sound as in folk, yolk
o+ll, which usually make the /oʊ/ sound as in roll, knoll, scroll
o+lt, which usually make the /oʊ/ sound as in bolt, volt
o+st, which usually make the /oʊ/ sound as in ghost, most, post
cy,which usually make the /-si:/ sound as in agency, fluency, efficiency
ity, which usually make the /əti/ sound as in quality, ability, reality
logy, which usually make the /ləʤi/ sound as in trilogy, apology, mythology
graphy, which usually make the /grəfi/ sound as in photography

Diphthongs

Diphthongs are the vowel version of blends. Rather than following the simple digraph rule, certain pairs of vowels such as "oy" in toy act like a blend and both sounds are pronounced. If toy followed the digraph rule, it would be pronounced as toe(/ˈtoʊ/). As with consonant clusters, diphthongs can pose a significant challenge to rule-oriented beginning readers. Technically a diphthong is a vowel sound produced when the tongue moves or glides from one vowel sound toward another vowel sound in the same syllable.

There are only three diphthong phonemes:

Diphthongs and triphthongs when are pronounced with the diphthong phoneme /aɪ/:

ei, which make the /aɪ/ sound as in heist
ey, which make the /aɪ/ sound as in eye, geyser
ie, which make the /aɪ/ sound as in die, tie, quiet, science
ye, which make the /aɪ/ sound as in dye, rye
eigh, which usually make the /aɪ/ sound as in height
igh, which usually make the /aɪ/ sound as in high, thigh, night, flight, wright
ign, which usually make the /aɪ/ sound as in sign, align, assign, benign
ind, which usually make the /aɪ/ sound as in bind, kind, mind, grind, behind
fy, which usually make the /aɪ/ sound as in notify, glorify
ky, which usually make the /aɪ/ sound as in sky


Diphthongs and triphthongs when are pronounced with the diphthong phoneme /aʊ/:

ou, which make the /aʊ/ sound as in out, round, bounce
ow, which make the /aʊ/ sound as in how, down, brow

Diphthongs and triphthongs when are pronounced with the diphthong phoneme /oɪ/:

oi, which make the /oɪ/ sound as in oil, coin, voice
oy, which make the /oɪ/ sound as in boy, and ploy

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