1. A method comprising: annotating data by inserting, via a processor and via a discriminative classification approach independent of using n-grams, boundary tags at boundaries in a speech utterance text based on weighted examples, wherein higher weights indicate more difficult examples, to yield annotated data; and iteratively repeating the annotating of the data, where each successive iteration has a longer turn than an immediately preceding iteration and each successive iteration is used to retrain a model associated with the discriminative classification approach.