Diphthongs: oi, oy, ou, ow Chapter Notes | Language Arts for Grade 1 PDF Download

Introduction

A diphthong is a vowel sound that glides from one vowel to another within the same syllable, creating a distinct sound. Diphthongs can appear at the start (e.g., out), middle (e.g., caught), or end (e.g., enjoy) of words, blending two vowels into a single sound.
Here are common diphthong pairs:

• ow (as in cow)
• ou (as in house)
• aw (as in law)
• au (as in pause)
• oi (as in coin)
• oy (as in boy)

Notice that some pairs produce the same sound: ow and ou both make /ou/, aw and au both make /aw/, and oi and oy both make /oi/.

Note: I also include oo (with sounds like in room and book) when teaching diphthongs, as it complements this phonics skill, even though it may not technically be a diphthong.

How to Teach Diphthongs

To make diphthongs manageable, I teach one pair at a time, focusing on the sound (phoneme) and its spellings (graphemes). In my From Sounds to Spelling program, I start with ou and explain, “O-U makes the /ou/ sound.” After practicing with activities, we move to ow, noting that “O-W also makes /ou/.”

• Example words for ou and ow: loud, sound, ground, mouth, house, town, frown, growl, power, shower.

Next, I teach aw and au, saying, “A-W makes /aw/,” followed by “A-U also makes /aw/.”

• Example words for aw and au: law, draw, yawn, straw, awful, caught, taught, pause, fault.

Then, I introduce oi and oy, explaining, “O-I makes /oi/, and O-Y also makes /oi/.”

• Example words for oi and oy: coin, join, soil, point, choice, voice, toy, boy, enjoy.

Finally, I teach oo, covering both sounds: “O-O makes /oo/ like in room,” and “O-O also makes a different sound, like in book.”

• Example words for oo: zoo, food, tool, soon, room, smooth, school, book, cook, good, took, stood.

When to Teach Diphthongs

I typically introduce diphthongs in 2nd grade, after students have mastered long vowel patterns. In my From Sounds to Spelling program, diphthongs are the final unit for 2nd grade.

Activities for Teaching Diphthongs

• Decodable Readers: Use texts with diphthongs for repeated practice.
• Word Building: Have students build words using magnetic letters or tiles.
• Highlighting Diphthongs: Ask students to mark diphthong words in a text before reading.
• Word Sorts: Sort words by diphthong pairs to reinforce patterns.
• Vocabulary Posters: Create posters with diphthong-rich words like snout, scowl, discount, or sprawl. Students can define, illustrate, and use these words in sentences.

Conclusion

Diphthongs may seem tricky, but teaching pairs that share the same sound (e.g., oi and oy) simplifies the process for students, making this phonics concept more accessible.