Graphical depiction of bivariate functional principal components analysis from Whistling shares a common tongue with speech: bioacoustics from real-time MRI of the human vocal tract

The tongue is traced and decomposed into functions Y and Z coordinates. The numerical parameters of the splines are treated as a multivariate dataset and subjected to PCA. Using the same basis set the results of PCA and be backconverted into functional space to produce fPCA components that are easily interpretable as a representation of tongue movements.