A phoneme is the smallest unit of sound in speech that can be used to make one word different from another, such as -p, -d, -m or -v. Phonemes are divided into two major categories: consonants and vowels.
Bid, bit; vat, van; tap, nap; hit, hip; ton, tan; vat, vet
A digraph is a type of a phoneme in which a single sound crafted by coupling two letters. A trigraph is a phoneme which is made of three letters, though many people will use the term “digraph” for both combinations. Some vary in sound depending on the words they are used in, notably “th” and “wh.”
Consonant List
KN, NG, CH, WR, CK, SH, GH, PH, WH, TH, MB, GN
Knight, fling, change, write, check, shower, ghost, laugh, phone, what, who, that, thirsty, lamb, gnarled
Vowel and Combo List
EI, IE, AY, AI, EE, OE, OA, OW
Being, pie, stay, street, shoe, oars, flower
Some digraphs are just doubles of a letter: zz, ss, ll, tt, ff. They generally make the simplest sound of the single letter.
Buzz, class, pill, letter, staff
If two or more consonants are used together but each letter can be heard individually, it is called a “consonant blend.”
Two: brake, snow, fruit, drive, glass, skate, trace, flare
Three: straw, spring, splinter, scroll