ABSTRACT
The presence of vowel errors in the speech of children with phonological disorders captured the attention of several researchers and clinicians in the 1980s and 1990s (e.g., Hargrove, 1982; Pollock & Keiser, 1990; Reynolds, 1990; Stoel-Gammon & Herrington, 1990; Gibbon, Shockey, & Reid, 1992). Their early studies provided detailed descriptions of the vowel errors produced by a variety of individuals and small groups of children, and raised numerous clinical and theoretical issues. Since that time, a number of researchers have explored the application of newer theoretical models to the description of vowel errors (e.g., Harris, Watson, & Bates, 1999; Bates, Watson, & Scobbie, 2002; Reynolds, 2002). However, many questions remained, such as: 1) How common are vowel errors? 2) Which vowels are most often produced incorrectly? 3) What types of vowel error patterns are most often used? and 4) Are the vowel errors produced by phonologically disordered children similar to those produced by younger children with typical phonological development? These questions could not be addressed with small group studies or studies in which the participants were selected because they were known to produce vowel errors.
