1. A tangible computer-readable medium storing instructions for controlling a computing device to detect morphemes using lattices in an automated task classification system which operates on one or more task objectives of a user, the instructions comprising: recognizing a lattice of phone strings in user input, the lattice representing a distribution over the phone strings; detecting morphemes in the user input using the recognized lattice; and making task-type classification decisions based on the detected morphemes in the user input.