We propose a shape-based variational framework to curve evolution for the segmen tation of tongue contours from MRI mid-sagittal images. In particular, we first build a PCA model on tongue contours of different articulations of a reference s peaker, and use it as shape priors. The parameters of the curve representation a re then manipulated to minimize an objective function. The designed energy integ rates both global and local image information. The global term extracts roughly the object in the whole image domain; while the local term improves precision in side a small neighborhood around the contour. Promising results and comparisons with other approaches demonstrate the efficiency of our new model.