English has two ways to spell the /aʊ/ sound (the sound in "out" and "cow"): the letters OU and OW. Native speakers almost never confuse these because there is a reliable position rule. Here is how it works.
The Rule: Position Determines Spelling
Use OW: at the end of a word or syllable, or before a final N or L.
Use OU: in the middle of a word before a consonant (not at the end).
OW at the End of Words
When the /aʊ/ sound comes at the very end of a word, English almost always uses OW:
OW Before N and L
OW also appears before a final N or L:
- Before N: town, gown, down, crown, brown, clown, frown, drown
- Before L: owl, fowl, growl, prowl, jowl, scowl, howl
OU in the Middle of Words
When the /aʊ/ sound appears in the middle of a word before another consonant, English uses OU:
Important: OW Also Says /oʊ/
Watch out: OW does not always say /aʊ/. OW also says the /oʊ/ sound (the long O sound) in many common words:
- /oʊ/ words: know, show, slow, grow, below, window, follow, yellow, elbow, shadow
- /aʊ/ words: now, how, cow, town, owl, down, brown
This is one of the trickiest patterns in English. The context usually makes it clear, and with practice you will recognize which sound to use.
OU Also Has Other Sounds
Similarly, OU does not always say /aʊ/. OU can also say:
- /uː/: you, group, soup, through, wound (verb)
- /ɒ/: cough, trough
- /ʌ/: young, touch, double, cousin, country
- /ɔː/: four, your, court, pour
This guide focuses on the /aʊ/ sound specifically. The key takeaway is: when OU or OW says /aʊ/, follow the position rule above.
Quick Summary
| Position | Spelling | Examples |
|---|---|---|
| End of word | OW | now, how, cow, bow |
| Before N | OW | town, down, brown, crown |
| Before L | OW | owl, howl, growl, fowl |
| Middle (before consonant) | OU | out, sound, mouth, house |