Spelling exercises: "ou" vs "ow"

The digraphs "ou" and "ow" often represent the same sounds (/aʊ/ and /əʊ/). However we can have two conclusions:
 * "ou" sonds /aʊ/ more often than /əʊ/
 * "ou" is never at the end of the word with either of these two sounds (e.g. "you" and "caribou" sound /uː/).

As /aʊ/

 * with "ou":
 * In the middle of the word: about - account - amount - announce - around - background - blouse - bound - boundary - cloud - compound - council - counsel - count - county - discount - doubt - encounter - flounder - foul - found - founder - ground - house - loud - mount - mountain - mouse - mouth - noun - out - outcome - output - pound - profound - proud - round - scout - shout - sound - south - surround - thousand - trout - wound (verb wind)


 * with "ow":
 * In the middle of the word: brown - browse - clown - crowd - crown - down - drown - frown - owl - powder - towel - town - vowel


 * At the end of the word: allow - bow (inclination) - brow - cow - eyebrow - how - now - row (quarrel) - wow

As /əʊ/

 * with "ou":
 * In the middle of the word: although - dough - shoulder - soul - though


 * with "ow":
 * In the middle of the word: bowl - grown - growth - owe - own


 * At the end of the word: arrow - below - blow - borrow - bow (for shooting arrows) - crow - elbow - fellow - flow - follow - grow - know - low - narrow - row (line) - shadow - show - slow - snow - throw - tomorrow - tow - window - yellow