Development of the MIT ASR system for the 2016 Arabic Multi-genre Broadcast Challenge

The Arabic language, with over 300 million speakers, has significant diversity and breadth. This proves challenging when building an automated system to understand what is said. This paper describes an Arabic Automatic Speech Recognition system developed on a 1,200 hour speech corpus that was made available for the 2016 Arabic Multi-genre Broadcast (MGB) Challenge. A range of Deep Neural Network (DNN) topologies were modeled including; Feed-forward, Convolutional, Time-Delay, Recurrent Long Short-Term Memory (LSTM), Highway LSTM (H-LSTM), and Grid LSTM (GLSTM). The best performance came from a sequence discriminatively trained G-LSTM neural network. The best overall Word Error Rate (WER) was 18.3% (p < 0:001) on the development set, after combining hypotheses of 3 and 5 layer sequence discriminatively trained G-LSTM models that had been rescored with a 4-gram language model.