The present study quantified cross-sectional tongue shape for vowels in a single plane using Principal Component Analysis. A single subject repeated eleven English vowels in two consonant contexts, five times. The first two PC's described two waveshapes and accounted for 93% of the variance in the data. They were model-free, and data-derived, thus representing underlying tongue shapes for this subject. The loadings of the eleven vowels on the first two PC's for this subject indicated three distinct shape groups: high vowels, front vowels, and back vowels.