The English digraph OO normally has two sounds: long /uː/ in food, moon, too and short /ʊ/ in book, foot, good. That covers 95% of OO words. The remaining 5% are exceptions, and four of them are very common: blood, flood, door, floor. Master these and OO becomes fully predictable.
The Four OO Sounds in English
| Sound | Frequency | Examples |
|---|---|---|
| /uː/ long OO | Most common | food, moon, too, soon, school |
| /ʊ/ short OO | Common | book, foot, good, look, took |
| /ʌ/ uh sound | Rare (3 words) | blood, flood, do (when in some compounds) |
| /ɔːr/ or-sound | Rare (with R) | door, floor |
The /ʌ/ Exceptions: Just Three Words
Only three common words pronounce OO as /ʌ/, the same vowel as in cup and but:
Note: derivatives keep the same vowel (bloody, flooded, bloodbath, floodgate). The /ʌ/ pronunciation is fossilized in this small word family.
The /ɔːr/ Exceptions: With R
When OO is followed by R, two common words use the /ɔːr/ sound (the same vowel as in more and store):
Compare with regular /uːr/ pronunciation (which is rarer): poor /pʊr/ or /pɔːr/, boor /bʊr/. Most OOR words follow door's pattern, not poor's. Note: moor /mʊr/ goes the short /ʊ/ way.
How to Predict the OO Sound
Without an exception list, the spelling cannot tell you reliably. But these heuristics work for most words:
- OO + K → almost always /ʊ/: book, look, took, hook.
- OO + D → usually /uː/ in food, mood; but check the famous trio good, hood, wood, stood which use /ʊ/. Blood, flood are the unique /ʌ/ exceptions.
- OO + R → usually /ɔːr/ in door, floor; check poor, moor for /ʊr/.
- OO + T → mixed: boot, root /uː/, foot, soot /ʊ/.
- OO + L, N, M, P, S, ZE → usually /uː/: school, moon, room, hoop, choose, snooze.
Why These Exceptions Exist
In Middle English, all OO words had a single sound, similar to /oː/ (long O). During the Great Vowel Shift (1400-1700), this shifted to /uː/, but in some words the change was incomplete or got reversed. Blood and flood shortened past /ʊ/ all the way to /ʌ/, a step further than book and good. Door and floor, influenced by the following R, kept a more open vowel. The spelling froze before the sounds finished moving.
The Trap List: OO Words That Look Similar but Sound Different
| Word | Sound | Word | Sound |
|---|---|---|---|
| food | /uː/ | good | /ʊ/ |
| blood | /ʌ/ | flood | /ʌ/ |
| door | /ɔːr/ | floor | /ɔːr/ |
| poor | /pʊr/ or /pɔːr/ | moor | /mʊr/ |
| boot | /uː/ | foot | /ʊ/ |
| moon | /uː/ | noon | /uː/ |
Brooch: A Special Case
The word brooch /broʊtʃ/ is its own exception: OO here sounds like long /oʊ/ (the vowel in boat). It is the only common word with this OO pronunciation. Some speakers spell it broach, which clears up the confusion. Brooch /broʊtʃ/ is a piece of jewelry; broach as a verb means to bring up a topic.
Practice Sentences
- The flood reached the door; blood was on the floor.
- I cooked good food in the cool room. (cool /uː/, good /ʊ/, food /uː/)
- She took a look through the door. (look /ʊ/, door /ɔːr/)
- The moon rose over the flooded floor.
Memory Trick
Memorize the four exceptions as a sentence: The blood from the flood covered the door and the floor. All four exceptions sit in one mental scene. Everything else with OO follows the predictable /uː/ or /ʊ/ rule, with /ʊ/ guaranteed before K.
Quick Summary
OO has four pronunciations: /uː/ (mostly), /ʊ/ (before K, also good/hood/wood/stood/foot), /ʌ/ (only blood and flood), /ɔːr/ (only door and floor). With these four exceptions memorized, the OO digraph stops being unpredictable.