Combining Joint Factor Analysis and iVectors for Robust Language Recognition

This paper presents a system to identify the spoken language in challenging audio material such as broadcast news shows. The audio material targeted by the system is characterized by a large range of background conditions (e.g. studio recordings vs. outdoor interviews) and a considerable amount of non-native speakers. The designed model-based language classifier automatically identifies intervals of Flemish (Belgian Dutch), English or French speech. The proposed system is iVector-based, but unlike the standard approach it does not model the Total Variability. Instead, it relies on the original Joint Factor Analysis recipe by modeling the different sources of variability separately. For each speaker a fixed-length low-dimensional feature vector is extracted which encodes the language variability and the other sources of variability separately. The language factors are then fed to a simple language classifier. When assessed on a self-composed dataset containing 9 hours of monolingual broadcast news, 9 hours of multilingual broadcast news and 10 hours of documentaries, this classifier is found to outperform a state-of-the-art eigenchannel compensated discriminativelytrained GMM system by up to 20% relative. A standard iVector baseline is outperformed by up to 40% relative.