Employing boosting to compare cues to verbal feedback in multi-lingual dialog

Verbal feedback provides important cues in establishing interactional rapport. The challenge of recognizing contexts for verbal feedback largely arises from relative sparseness and optionality. In addition, cross-language and inter-speaker variations can make recognition more difficult. In this paper, we show that boosting can improve accuracy in recognizing contexts for verbal feedback based on prosodic cues. In our experiments, we use dyads from three languages (English, Spanish and Arabic) to evaluate two boosting methods, generalized Adaboost and Gradient Boosting Trees, against Support Vector Machines (SVMs) and a naive baseline, with explicit oversampling on the minority verbal feedback instances. We find that both boosting methods outperform the baseline and SVM classifiers. Analysis of the feature weighting by the boosted classifiers highlights differences and similarities in the prosodic cues employed by members of these diverse language/cultural groups.