Some parametric curves (polynomials and discrete cosine transforms) were fitted to the formant trajectories of a series of Spanish vocalic sequences in order to analyze their suitability for forensic voice comparison. The estimated coefficient values from the parametric curves were used as input to a generative multivariate-kernel-density formula for calculating likelihood ratios expressing the probability of obtaining the observed difference between two speech samples under two opposing hypotheses: that the samples were produced by the same speaker and that the samples were produced by different speakers.