/ʊ/ — the BOOK vowel as in book, put, good

About this sound

This is one of the rarest vowels in English — only about 80 words use it.

Don't confuse /ʊ/ with /u/ (the MOON vowel). Compare: book (short) vs moon (long), pull vs pool, full vs fool.

Main spellings (~95%)

⟨oo⟩ ~65%

⟨u⟩ ~30%

Unusual spellings (~5%)

⟨ou⟩

The silent ⟨l⟩ is a clue — these three are the only common words.

⟨o⟩

/ʊ/ vs /u/

Don't confuse /ʊ/ with /u/! /ʊ/ is short and relaxed, /u/ is long and tense. Compare: book vs moon, pull vs pool, full vs fool.