Preschool children (mean age of 4 years, 6 months) imitated 15 synthesized formant patterns representing both English and alien vowels. The first three formant frequencies of the imitations were measured from spectrograms. Generally, the children were successful in reproducing the relative formant patterns of the stimuli, although they tended to produce alien vowels as proximal English vowels. The reliability of imitation was better for stimuli modeled on English vowels. Combined with earlier results for men, women, and six‐year‐old children, the data are consistent with nearly straight isovowel lines in theF–FandF–Fplanes. The most linear relationship, with a good separation of the mean data for four age–sex groups, was noted for vowel [i]. The results for preschoolers, like those for adult subjects, indicate that the precision of vowel imitation is limited as much, if not more, by auditory resolution as by motor‐articulatory performance, because the formant variability in imitation is commensurate with data on difference limens for vowel formant frequency.