What Happens When Sounding Out Isn’t Enough?

Why Set for Variability Matters

We often think of decoding as a fairly straightforward process: look at the letters, match them to their corresponding sounds, blend, and read. And for many words, that’s exactly how it works.

But English doesn’t always play by the rules.

Unlike languages such as Finnish or Italian, where the relationship between the letters and sounds they represent is relatively consistent and predictable, English has what researchers call a deep orthography. That means the way words are spelled doesn’t always clearly reflect how they’re pronounced. In English, the same letter can make different sounds in different words: the letter ‘a’ sounds different in cat, cake, and father, and the /sh/ sound shows up in words as varied as ship, chef, and nation. Even vowel combinations like ea can be unpredictable. Consider bead versus head.

So, what happens when a child applies their phonics knowledge to decode words and still ends up with something slightly off? Take the word scorpion. A child might decode it as skor-pee-on. It’s not quite right, but often, they’ll still manage to land on the correct word. How?

This is where the concept of Set for Variability comes in.

Set for Variability (SfV) refers to a child’s ability to mentally adjust an imperfect pronunciation and connect it to a word they already know. It’s a kind of linguistic flexibility, an internal nudge that says, ‘That doesn’t sound quite right. I’ll try again’.

Beyond Code: Why It Matters for Real-World Reading

Phonics instruction is essential for learning to read, but in English, where spelling and sound can diverge, decoding alone doesn’t always get a child to the right word. Researcher Richard Venezky recognised this decades ago. While being a strong advocate for phonics instruction, Venezky pointed out that for children to be successful readers in English, they needed more than just decoding skills. They needed a kind of adaptability. As he explained, ‘if what is first produced does not sound like something already known from listening, a child has to change one or more of the sound associations (most probably a vowel) and try again’ (1999, p. 232). In other words, reading in English involves more than rule-following, it requires reasoning, problem-solving, and flexible use of language knowledge.

SfV is often measured through tasks that ask children to correct regularised mispronunciations (eg. decoding ‘wasp’ as waesp but adjusting it to read wasp). Longitudinal research shows that this ability is a strong predictor of word reading success, particularly in English, where many words defy straightforward decoding (Elbro et al., 2012). More recently, Laura Steacy’s work has helped clarify just how important SfV is. Her studies show that children who can revise their decoding attempts, even when their first try is inaccurate, are more successful in reading irregular or unfamiliar words (Steacy et al., 2019). These children aren't just sounding out; they’re testing, adjusting, and matching what they read to words they know. This flexible thinking turns approximation into recognition.

Crucially, Steacy and colleagues also found that this skill is closely tied to a child’s oral vocabulary. Children with richer language knowledge are better equipped to make these adjustments (Steacy et al., 2022). And her longitudinal findings show that SfV continues to play a role in reading development over time, especially in a language as complex as English (Steacy et al., 2023). Taken together, these findings make one thing clear: Set for Variability is not optional. It’s a vital part of skilled reading. And it may help explain why some children still struggle even after receiving strong phonics instruction. They know how to decode, but not how to adapt when decoding doesn’t deliver a clear answer.

The Role of Oral Vocabulary: Why What Children Know Matters

One of the most important supports for SfV is a child’s oral vocabulary. Quite simply, children can only match a decoded word to a word they already know. If a word doesn’t exist in their spoken vocabulary, there’s nothing for the brain to connect it to even if their decoding attempt is reasonably close.

Imagine a child decodes the word apron as ‘a-per-on’ If they’ve never heard the word apron before, their brain has no reference point. But if they’ve seen someone wear one, talked about it in pretend play, or heard the word in other books, they’re much more likely to revise their pronunciation and land on the correct word. Without that background knowledge, even the most accurate decoding may fall flat. In other words, the more spoken words a child knows, the better equipped they are to adjust, evaluate, and match decoded attempts to known language.

This is especially relevant for teachers. Vocabulary isn’t just about comprehension, it’s also foundational to accurate word recognition. When children have a large reservoir of known words in their oral vocabulary, their brains are better prepared to make connections, resolve ambiguities, and correct decoding errors.

When Texts Are Too Decodable

While decodable texts are essential for early readers, especially those still mastering letter-sound correspondences, it’s worth noting that 100% decodable texts don’t offer opportunities to practise Set for Variability. In fully decodable texts, every word follows predictable phonics rules. That means children aren’t required to flex, adjust, or resolve mismatches between decoding and meaning because there aren’t any. These texts are useful for building decoding accuracy and confidence, but they don’t challenge children to use the mental flexibility that SfV supports.

To develop this skill, children need some exposure to less regular words, ie. words that don’t map perfectly from print to speech. This is where rich, high-quality texts come in. They provide opportunities for children to decode, stumble, adjust, and ultimately recognise a word based on how it sounds, what it means, and how it fits in the sentence. If we want children to develop SfV, we need to give them room to practise it. That means a balance of texts; some that support decoding, and others that stretch their flexibility and language knowledge.

Practical Ways to Support Set for Variability

Set for Variability isn’t something we teach in a standalone lesson. But there are small, intentional ways to support it every day:

• Model flexible thinking
  Make use of thinking aloud when reading to children: ‘Hmm… that didn’t sound quite right. Could it be another word we know?’ Show children that skilled readers adjust when something feels off and that rereading with intention is part of the process.

• Introduce vowel flexing
  Teach children how to ‘flex’ or ‘flip’ the vowel sound when a decoded word doesn’t make sense as very often, it is the vowel representation that needs to be flexed. For example, if a child reads ‘head’ as ‘heed’, guide them to try a different vowel sound: ‘What happens if we try the short /e/ sound instead?’ This allows readers to self-correct using what they know about how English works.

• Use oral language strategically
  Engage children in rich conversations and expose them to complex vocabulary. The more spoken language they encounter, the more options they can draw upon when decoding unfamiliar words.

• Expose children to a wide range of words
  Read both narrative and informational texts. Discuss new vocabulary as it arises, explicitly teach vocabulary and revisit words in multiple contexts to reinforce their meaning and pronunciation.
  

Final Thoughts: Why It Deserves More Attention

Set for Variability reminds us that reading is deeply cognitive and linguistic. For some children, this kind of flexibility develops quickly. For others, it must be supported more explicitly through the development of rich oral language, offering meaningful exposure to vocabulary, and providing opportunities to explore words that don’t follow predictable patterns. SfV also highlights the vital role of spoken language in reading development. Oral vocabulary isn’t just helpful, it’s essential. The words children hear, discuss, and internalise become the foundation for recognising and understanding words in print.

So the next time a child decodes a word that’s close but not quite right, pause before correcting. Instead, celebrate the attempt, nudge the tweak, and know that you’re helping them build a skill that matters more than we once realised.