1. A computer-implemented method of automatically generating a scoring model for scoring a speech sample to characterize speaking proficiency, the method comprising: receiving one or more training speech samples in response to a prompt; determining one or more speech features for each of the training speech samples, wherein the speech features include a previously assigned score, wherein the previously assigned score is assigned by a human rater based on a training speech sample; and generating a scoring model using a computer based on the speech features, wherein the scoring model is effective for scoring spontaneous speech responses; wherein the scoring model is independent of speech recognition accuracy associated with the training speech samples; wherein the scoring model is used to generate a numeric speaking proficiency score for a received spontaneous speech response.