Detection of nonverbal vocalizations using Gaussian Mixture Models: looking for fillers and laughter in conversational speech

In this paper, we analyze acoustic profiles of fillers (i.e. filled pauses, FPs) and laughter with the aim to automatically localize these nonverbal vocalizations in a stream of audio. Among other features, we use voice quality features to capture the distinctive production modes of laughter and spectral similarity measures to capture the stability of the oral tract that is characteristic for FPs. Classification experiments with Gaussian Mixture Models and various sets of features are performed. We find that Mel-Frequency Cepstrum Coefficients are performing relatively well in comparison to other features for both FPs and laughter. In order to address the large variation in the frame wise decision scores (e.g., log-likelihood ratios) observed in sequences of frames we apply a median filter to these scores, which yields large performance improvements. Our analyses and results are presented within the framework of this year's Interspeech Computational Paralinguistics sub-Challenge on Social Signals.