Understanding Diphthongs: A Foundational Guide for Teachers in Remedial Reading Classrooms

Introduction

Reading difficulties among early-grade learners often emerge not only from problems with letter recognition or blending but also from challenges in perceiving and producing complex vowel sounds. One such area of difficulty is the understanding of diphthongs, also known as gliding vowel sounds.

A diphthong is a speech sound in which one vowel sound glides into another during pronunciation. Unlike pure vowels, where the mouth remains relatively stable, diphthongs involve noticeable movement of the tongue, lips, or jaw.

Research in phonemic awareness and early literacy suggests that explicit instruction in sound discrimination, articulation, and sound-symbol association significantly improves decoding and reading fluency among low achievers. Therefore, diphthongs should be taught as meaningful sound experiences that children can hear, feel, observe, and apply while reading.

What Are Diphthongs?

The term diphthong comes from Greek and means “two sounds.” In English, diphthongs occur when two vowel sounds combine and glide smoothly within one syllable.

Why Do Learners Struggle with Diphthongs?

Many struggling readers decode by focusing only on letters rather than listening carefully to sounds, so they may miss the sound transition within diphthongs.

The Importance of Auditory Discrimination

Before learners can read diphthong words accurately, they must first learn to hear differences between sounds.

• day vs do
• boy vs bay
• cow vs coat

Articulation and Mouth Movement in Diphthong Instruction

Diphthongs involve visible mouth movement, making them ideal for multisensory teaching.

• /ei/ often moves from open mouth to smile shape
• /oi/ begins with rounded lips and glides outward
• /au/ involves wide opening followed by rounding

Teachers can strengthen sound memory by exaggerating pronunciation and encouraging mirror/peer observation.

Pattern Recognition: Supporting, Not Dominating, Learning

Spelling patterns should be introduced as clues rather than rigid rules. For example, /oi/ may appear as oi (coin) or oy (boy).

“What letters do you notice?” • “Does this word sound like boy or day?” • “Which words sound alike?”

The Role of Multisensory Activities in Diphthong Learning

Activities involving movement, speaking, listening, touch, and visual recognition are especially effective for struggling readers.

• sound-family grouping
• diphthong sorting games
• foldable sound cards
• gesture-based sound modelling
• peer reading circles

Teaching Exception Words

Words like said, rough, and done do not follow expected patterns and should be taught as special words through repeated exposure and recognition practice.

“Most words follow patterns, but some special words must be remembered.”

Classroom Implications for Remedial Teachers

Instruction should progress gradually:

• Sound exposure
• Listening discrimination
• Articulation awareness
• Sound comparison
• Guided reading
• Pattern observation
• Independent application

Teacher language matters: asking “What sound do you hear?” keeps learners focused on phonemic awareness.

Conclusion

Diphthongs are an essential part of early reading development, but for struggling readers they can cause confusion unless taught through explicit, multisensory, sound-focused methods. When instruction prioritizes auditory awareness and guided discovery, learners build confidence, fluency, and decoding ability.