Vowel team OU makes several sounds. For now, we are going to focus on its most common sound, /ou/, as in “scout”. 

/ou/, /ou/, /ou/, scout.

Vowel team OU is more commonly used to spell /ou/ when in the middle of a word or syllable than vowel team OW.

However, if /ou/  is followed by consonants N or L, vowel team OW is more common, as in “frown” or “scowl”.

Vowel team OW is more commonly used to spell /ou/ when it is at the end of a word, as in “cow”.