The purpose of this research is to determine if children with reading difficulties produce vowels with greater variability than children with normal reading ability. The vowels chosen for this study are /ɪ/, /ε/, and /æ/, occurring in real and nonsense monosyllabic words. Our past research, examining spectral variability in vowels produced by first grade students as a function of whether they were reading words presented individually in random or blocked format, revealed no systematic effect of presentation format on variability [K. Baker, A. Fowler, and F. Bell-Berti, J. Acoust. Soc. Am. 110, 2704 (2001)]. The purpose of this present study is to determine if good and poor readers differ in vowel duration variability. [Work supported by U.S. Dept. of Education, McNair Scholars Program.]