The letters OW are one of the trickiest spelling patterns in English. Unlike many letter combinations that map to a single sound, OW regularly produces two completely different vowel sounds: the diphthong /aʊ/ (as in "cow") and the diphthong /oʊ/ (as in "low"). This can be confusing for learners, but the good news is that there are reliable patterns that help you predict the correct pronunciation most of the time.
In this guide, we will break down both sounds, explore the rules that govern them, examine the exceptions, and give you plenty of practice with interactive word cards.
The Two Sounds of OW: Overview
Before we explore the patterns, here is a quick comparison of the two sounds:
| Sound | IPA | Examples | Description |
|---|---|---|---|
| OW as in "cow" | /aʊ/ | cow, now, how, down, town | Mouth opens wide, then rounds. Same sound as OU in "out." |
| OW as in "low" | /oʊ/ | low, know, show, grow, snow | Lips round throughout. Same sound as O in "go." |
Both sounds are diphthongs, meaning the vowel glides from one position to another. For /aʊ/, your mouth starts open and moves to a rounded position. For /oʊ/, your lips stay more rounded from start to finish.
Pattern 1: OW at the End of a Word = /oʊ/ (Usually)
When OW appears at the end of a word (especially in one-syllable words or at the end of a stressed syllable), it is often pronounced /oʊ/.
The rule: Final OW = /oʊ/
More examples: slow, blow, throw, tow, mow, row (a line), bow (of a ship), below, follow, window, elbow, pillow, shallow, yellow
Important exception: Several common words ending in OW use /aʊ/ instead: cow, how, now, wow, bow (to bend), plow, vow, brow. These are among the most frequent words in English, so they must be memorized.
Pattern 2: OW before N = /aʊ/ (Usually)
When OW is followed by the letter N, it almost always produces the /aʊ/ sound.
The rule: OW + N = /aʊ/
More examples: frown, gown, drown, clown, downtown, renown, noun (spelled OU, but same pattern)
Key exception: The word "own" is pronounced /oʊn/, not /aʊn/. Similarly, "shown" = /ʃoʊn/, "grown" = /ɡroʊn/, "blown" = /bloʊn/, "known" = /noʊn/, and "thrown" = /θroʊn/. These are all past participle forms of verbs that already use /oʊ/ (show, grow, blow, know, throw). The /oʊ/ sound carries over from the base verb.
Pattern 3: OW before D = /aʊ/ (Usually)
When OW appears before the letter D, it tends to be pronounced /aʊ/.
The rule: OW + D = /aʊ/
More examples: chowder, crowded, rowdy, howdy
Exception: "owed" = /oʊd/ (past tense of "owe"). Also, "showed" = /ʃoʊd/, "mowed" = /moʊd/, and other past tenses of /oʊ/ verbs keep the /oʊ/ sound.
Pattern 4: OW before ER = /aʊ/ (Usually)
When OW comes before ER, the pronunciation is almost always /aʊ/.
The rule: OW + ER = /aʊ/
More examples: however, towel, vowel, coward, Howard
Exception: "lower" = /ˈloʊɚ/ (from "low"), "mower" = /ˈmoʊɚ/ (from "mow"), "grower" = /ˈɡroʊɚ/ (from "grow"). Words derived from /oʊ/ base forms keep their pronunciation.
Pattern 5: OW before L = /oʊ/ (Usually)
When OW is followed by the letter L, it tends to be /oʊ/.
The rule: OW + L = /oʊ/
Big exception: The word "owl" is pronounced /aʊl/, not /oʊl/. Likewise, "growl" = /ɡraʊl/, "prowl" = /praʊl/, "howl" = /haʊl/, "fowl" = /faʊl/, and "jowl" = /dʒaʊl/ all use /aʊ/. So OW + L is actually split between both pronunciations, making this pattern less reliable than the others.
Tricky Words: OW with Two Pronunciations
Some English words spelled with OW can be pronounced either way, depending on their meaning. These are true homographs (same spelling, different sounds, different meanings).
| Word | /oʊ/ Meaning | /aʊ/ Meaning |
|---|---|---|
| row | /roʊ/ a line of things ("a row of chairs") | /raʊ/ an argument ("they had a row") |
| bow | /boʊ/ a tied ribbon; front of a ship ("a bow tie") | /baʊ/ to bend forward ("take a bow") |
| sow | /soʊ/ to plant seeds ("sow the field") | /saʊ/ a female pig ("the sow and her piglets") |
For these words, context is the only way to determine the correct pronunciation. Pay attention to the meaning of the sentence.
Quick Reference Table: OW Pronunciation Rules
| Pattern | Sound | Examples | Reliability |
|---|---|---|---|
| OW at end of word | /oʊ/ | show, grow, flow, snow | High (but cow, how, now are exceptions) |
| OW + N | /aʊ/ | down, town, brown, crown | High (but own, shown, grown are exceptions) |
| OW + D | /aʊ/ | crowd, powder, chowder | High |
| OW + ER | /aʊ/ | power, tower, flower, shower | High (but lower, mower are exceptions) |
| OW + L | /oʊ/ | bowl | Low (owl, howl, growl are /aʊ/) |
Practice: Which Sound Is It?
Test yourself. For each word, decide if OW is /aʊ/ or /oʊ/ before checking the answer:
- know → /oʊ/ (final OW)
- frown → /aʊ/ (OW + N)
- below → /oʊ/ (final OW)
- crowd → /aʊ/ (OW + D)
- tower → /aʊ/ (OW + ER)
- own → /oʊ/ (exception to OW + N)
- plow → /aʊ/ (exception to final OW)
- bowl → /oʊ/ (OW + L)
- owl → /aʊ/ (exception to OW + L)
- throw → /oʊ/ (final OW)
Additional Practice Words
Practice these words grouped by their sound to build muscle memory:
/aʊ/ Words (like "cow")
/oʊ/ Words (like "low")
Tips for Mastering OW
- Learn the base verb first: If a word is derived from a verb with /oʊ/ (like show → shown → shower... wait, "shower" is actually /aʊ/!), the past participle usually keeps /oʊ/. But be careful: "shower" is not from "show."
- OW + N is your most reliable rule: Almost all OW + N words use /aʊ/, with "own" and past participles (shown, grown, blown, known, thrown) as the main exceptions.
- Memorize the common /aʊ/ words ending in OW: cow, how, now, wow, bow (bend), plow, vow, brow. There are not many of them.
- Context resolves homographs: For "row," "bow," and "sow," the meaning of the sentence tells you which sound to use.
- Practice both sounds side by side: Say "cow" then "low," "now" then "know," "how" then "show." Feeling the difference between /aʊ/ and /oʊ/ in quick pairs will train your ear and mouth.