Digraphs: sh, ch, th, wh, and ck, and how they differ from blends

A digraph is two letters that spell one sound. Reading Universe defines it that way, with ph in phone and oa in boat, and it says the first digraphs to teach are the consonant pairs. The most common consonant digraphs on that page are ch, sh, th, wh, and ph. In phonics, that is the set to teach after children can read consonant-vowel-consonant words.

A consonant digraph is that same idea limited to consonants. sh in ship is a consonant digraph. oa in boat is a vowel digraph, taught later with vowel teams.

sh, ch, th, wh, and ck

Teach one pair at a time. Each new pair is one new sound, then words built like CVC words: the digraph is one tile in the blend, not two.

Pair	Sound	Words
sh	/sh/	ship, shop, shut, fish, dish, wish
ch	/ch/	chip, chat, chop, chin, much, rich
th	/th/ as in thin, or the voiced sound in this	thin, path, math, this, that, them
wh	/w/ as in when	when, whip, which
ck	/k/	back, pack, sick, duck, lock, neck
ph	/f/	phone

ph is in the common set, and phone is the example Reading Universe uses. It is a later word than ship. Teach sh, ch, and th before ph.

th has two sounds. thin, path, and math use the quiet one. this, that, and them use the voiced one. Teach the quiet sound in decodable words first, then show the voiced sound in the common words children already say.

wh is one sound in when and whip for most US speakers. Do not ask children to say each letter.

ck is the /k/ spelling at the end of a short-vowel word. It is a digraph, and it has a position rule. That rule is below.

Ten examples, if you need a short set to post: ship, chip, thin, when, back, fish, chat, path, duck, phone. Those ten are digraphs. stop, flag, and blend are not.

Digraph or blend

Say the word slowly and count sounds.

• ship: /sh/ /i/ /p/. Three sounds, four letters. sh is a digraph.
• stop: /s/ /t/ /o/ /p/. Four sounds, four letters. st is a blend. Each letter keeps its sound.
• chat: digraph. flag: blend.
• ch is a digraph, not a blend. th is a digraph, not a blend.

A word can hold both. crush is /k/ /r/ /u/ /sh/. cr is a blend. sh is a digraph. That is the "blend digraph" example people ask for: not one pattern, a word that contains each. branch works the same way: br is a blend, ch is a digraph.

The practice guide tells teachers to treat a digraph as one unit, and to sound each letter in a blend instead of memorizing the blend as a chunk. Teach each sound in a blend, then blend them. The full blend lists are on consonant blends.

What is not a digraph:

• A blend: bl, st, tr, fl. Two sounds.
• A single letter: s, h, c.
• tch: three letters, one sound, as in match. That is a trigraph. Reading Universe lists -tch as its own short-vowel spelling rule, beside the digraphs, not as ch.
• qu: /k/ and /w/, two sounds. It fails the one-sound test.

A trigraph is three letters and one sound. tch in match, catch, fetch, witch, and notch is the one children meet next to ch. ch after a consonant, as in lunch and bench, stays ch. You do not add t.

The ck spelling

Reading Universe teaches ck after short vowels and closed syllables, in words like luck and pack. The rule applies to one-syllable words. The position it teaches is immediate: after a short vowel, at the end of a one-syllable word, as in luck and pack.

Word	Why ck or not
pack, back, sack	Short a, one syllable, /k/ right after the vowel
sick, kick	Short i
duck, luck	Short u
lock, rock	Short o
neck	Short e
milk	A consonant sits between the vowel and /k/, so it is not "immediately after" the vowel. Spell k.
bake	Long a with silent e. The same page spells that final /k/ as ke, as in bake.

Children then know three spellings of /k/: c, k, and ck. At the start of a word they already use c in cat and k in kit. ck is the end spelling after a short vowel, not a starting spelling.

ck words to post: back, pack, sack, sick, kick, duck, luck, lock, rock, neck.

When to teach them

Single letters and CVC words come first. The practice guide says to present consonants and short vowels spelled by single letters first, then introduce blends and common two-letter consonant digraphs such as sh, th, and ch. Kindergarten and 1st grade are on that timeline. There is no single age.

Digraphs or blends first is a choice, not a law. Digraphs first is the smoother path: ship is still three sounds, so the blending routine from CVC words still works. Blends add a fourth sound. Either way, do not open sh, ch, th, wh, and ck in one day. One pair, then words, then the next pair.

There is no official list of twenty-one consonant digraphs, and no official set of seven, for a K-2 lesson. Teach the five common consonant pairs, then ck, then ng with the glued sounds, and leave vowel digraphs for their own unit. A page that numbers twenty-one pairs is counting spellings from the whole language, including rare ones a six-year-old will not read.

One limit

A child can chant "sh says /sh/" and still not read ship. The test is the word, tapped left to right, with the digraph as one sound. If the child says /s/ /h/, go back to the pair as a unit, which is what the practice guide requires, and read three words before you add a game.

Digraph books in the K-2 Decodable Books set include phonics wall cards for the units, sound cards and heart-word cards, ready to print. Nothing ships, and print PDFs are US Letter only.