Ask five different phonics programs how to teach sh and bl and you'll get five slightly different answers about which comes first — but every one of them agrees these are two different kinds of pattern, taught for different reasons. Mixing them up is one of the most common early-phonics stumbles, for teachers as much as for kids, so it's worth pinning down the actual difference before you plan a single lesson.
The one-sentence difference
In a digraph, two (or more) letters make one new sound that's different from either letter alone — sh, ch, th, wh, ph. In a blend, two or three consonants sit next to each other but each one keeps its own sound — you can still hear both letters if you slow the word down: bl, cr, st, spl.
Say "ship" slowly and you hear one sound where the s and h are — /sh/. Say "stop" slowly and you can still hear both /s/ and /t/ blending into each other. That's the entire distinction. Everything else is just examples and sequencing.
Common digraphs
- sh — ship, wish, shell
- ch — chip, lunch, chair
- th — this, math, three
- wh — when, whale, wheel
- ph — phone, dolphin, graph
Common blends
- L-blends — bl, cl, fl, gl, pl, sl (black, clap, flag)
- R-blends — br, cr, dr, fr, gr, pr, tr (crab, drum, frog)
- S-blends — sk, sm, sn, sp, st, sw (skip, snap, stop)
Why the mix-up happens
Both patterns are two-consonant clusters, both show up constantly in early reading, and both get introduced around the same stage — so it's an easy pair to blur together, especially since kids are simultaneously learning that letter combinations sometimes do unexpected things. The visual footprint looks almost identical on the page; the difference only shows up in the ear.
Which one to teach first
Reading Rockets' Phonics: In Practice guide recommends introducing digraphs before blends. The reasoning is straightforward: a digraph is one new sound to learn — a clean, single association. A blend asks a student to do something harder: hold onto two sounds they already know and say them in rapid sequence without merging them into a new, invented sound. That's a bigger cognitive lift, so it goes second.
It's also worth explicitly telling students blends are not a new sound to memorize — the guide notes that trying to teach a blend as a single fused unit actually makes it harder, since it adds an extra thing to memorize instead of just applying two known letter-sounds back to back.
A simple test to check understanding
Say a word slowly, stretching it out, and ask: "did that sound stay one sound, or could you hear two?" Ship stays one sound (digraph). Slip splits into two (blend). This single question does more to cement the distinction than any worksheet, because it puts the decision back on listening rather than memorized letter pairs.
Practice digraphs and blends with ABZ
ABZ's World of Phonics Obby: Digraphs gives kids fast, low-stakes reps identifying digraphs inside a Roblox-style obby. Free to try, no account required.
FAQs
Should I teach blends and digraphs in the same lesson?
Most sequences introduce them separately, with digraphs first — mixing them in the same lesson before either is solid tends to reinforce the confusion rather than resolve it.
Is "str" in "string" a blend or something else?
It's still a blend — a three-letter consonant cluster where all three sounds (/s/ /t/ /r/) remain audible, just like a two-letter blend, only longer.
What about "ck" in "duck" — is that a digraph?
Yes. Ck represents a single /k/ sound, so it follows the same one-sound rule as sh, ch, and th, even though it looks a bit different from the others.