1. In an automatic speech processing system, a method for assessing pronunciation of a student speech sample using a computerized acoustic segmentation system, the method comprising: accepting said student speech sample which comprises a sequence of words spoken by a student speaker; operating said computerized acoustic segmentation system to define sample acoustic units within said student speech sample based on speech acoustic models within said segmentation system, said speech acoustic models being established using training speech data from at least one speaker, said training speech data not necessarily including said sequence of spoken words; measuring duration of said sample acoustic units; and comparing said durations of sample acoustic units to a model of exemplary acoustic unit duration to compute a duration score indicative of similarity between said sample acoustic unit durations and exemplary acoustic unit durations.