Improvements in RWTH LVCSR evaluation systems for Polish, Portuguese, English, urdu, and Arabic

In this work, Portuguese, Polish, English, Urdu, and Arabic automatic speech recognition evaluation systems developed by the RWTH Aachen University are presented. Our LVCSR systems focus on various domains like broadcast news, spontaneous speech, and podcasts. All these systems but Urdu are used for Euronews and Skynews evaluations as part of the EUBridge project. Our previously developed LVCSR systems were improved using different techniques for the aforementioned languages. Significant improvements are obtained using multilingual tandem and hybrid approaches, minimum phone error training, lexical adaptation, open vocabulary long short term memory language models, maximum entropy language models and confusion-network based system combination.