Discriminative Articulatory Models for Spoken Term Detection in Low-Resource Conversational Settings

We study spoken term detection (STD) - the task of determining whether and where a given word or phrase appears in a given segment of speech - using articulatory feature-based pronunciation models. The models are motivated by the requirements of STD in low-resource settings, in which it may not be feasible to train a large-vocabulary continuous speech recognition system, as well as by the need to address pronunciation variation in conversational speech. Our STD system is trained to maximize the expected area under the receiver operating characteristic curve, often used to evaluate STD performance. In experimental evaluations on the Switchboard corpus, we find that our approach outperforms a baseline HMM-based system across a number of training set sizes, as well as a discriminative phone-based model in some settings.