Frame-based phonotactic Language Identification

This paper describes a frame-based phonotactic Language Identification (LID) system, which was used for the LID evaluation of the Robust Automatic Transcription of Speech (RATS) program by the Defense Advanced Research Projects Agency (DARPA). The proposed approach utilizes features derived from frame-level phone log-likelihoods from a phone recognizer. It is an attempt to capture not only phone sequence information but also short-term timing information for phone N-gram events, which is lacking in conventional phonotactic LID systems that simply count phone N-gram events. Based on this new method, we achieved 26% relative improvement in terms of C_avg for the RATS LID evaluation data compared to phone N-gram counts modeling. We also observed that it had a significant impact on score combination with our best acoustic system based on Mel-Frequency Cepstral Coefficients (MFCCs).