D is for digraph
You can guess at the meaning of digraph because di— means “two” and —graph means “something written.” A digraph is two letters that have one sound. In older forms of English, the two letters might be run together, such as ae (æ). In vowel digraphs, the second letter is usually silent. English dialects introduce some variation in pronunciation.
Note: Digraphs are letters.
ch chew
ck check
dg judge
ng doing
sh shout
th that, think
ph pheasant
wh what, when, where, who
ae archaeology [formerly, archæology]
ai maid, maintain
au audit
ay day, tray
ea bean, eat, teach
ee fleece, sweet
ei eight, receive
ey key
ie die
oa boat, coast
oe potatoes
oo book, look
ow slow
ue true
D is for diphthong
Diphthong also begins with di— for “two”, but the second part of the word is derived from a difficult Greek word, phthong, meaning “sound” but also related to “tongue”.
A diphthong is (1) two vowels that act together to create a sliding sound within a syllable (the letters Y and W often act as vowels in this instance). It is also (2) two sounds that slide within one vowel (not a digraph). English dialects introduce some variation in pronunciation.
Note: Diphthongs are sounds.
a rate, table
ai fail, rain
au daughter, haul
aw draw, hawk
ea create, eagle, great
ei height
ew dew, jewel, new
ey convey, obey
i arrive, high, private, sign
ia dial, trial
ie science
io pioneer, riot, violet
o ago, no, roll
oe poet
oi coil, noise, stoic
oo cool, fool, moon
ou out, mouse, soul
ow down, how, know, throwing
oy boy, oyster, voyage
ua casual
ue statue
uy buyer, Gruyère, guy
y by, hype, sky
yi flying, trying
Exercises
- Try to pronounce the word diphthong. Do you prefer to say “dip-thong” or “diff-thong”?
- Sound out words to identify digraphs and diphthongs. Which ones are the most commonly used?
English Manual: Letter by Letter 