1. A method of classifying input data representing speech input by a user of a speech application as belonging to one of a plurality of classifications, the plurality of classifications associated with a respective plurality of clusters that were fit to training data representing a plurality of speech utterances associated with the speech application, the method comprising: using at least one processor to perform: obtaining a first transformation generated based, at least in part, on a plurality of representative vectors determined from the training data, the plurality of representative vectors including at least one representative vector determined for each of the plurality of classifications, wherein the plurality of clusters were fit to the training data at least in part by fitting the plurality of clusters to transformed training data obtained by applying the first transformation to the training data; transforming the input data using at least the first transformation to obtain transformed input data representing the speech input by the user of the speech application; comparing the transformed input data to the plurality of clusters to determine which cluster of the plurality of clusters the input data should be associated with; and classifying the input data according to a classification of the plurality of classifications associated with the determined cluster.