The vowel harmony in Akan is described as a phonological process of regressive assimilation (i.e. advanced vowels assimilate unadvanced ones that precede them (Owusu 2002). Dolphyne (1988) devotes a section of her book to Akan vowel harmony. She identifies six groups of words that deviate from the Akan vowel harmony rule. Some of the words discussed in Dolphyne (1988) as exceptions to the Akan vowel harmony rule do not break the vowel harmony rule in the language. This is because unadvanced vowels cannot assimilate advanced vowels that precede them. Rather, it is the advanced vowels that assimilate unadvanced ones that precede them. In effect, there are virtually no exceptions to the vowel harmony rule in Akan.