Domain Adaptation of a Broadcast News Transcription System for the Portuguese Parliament

The main goal of this work is the adaptation of a broadcast news transcription system to a new domain, namely, the Portuguese Parliament plenary meetings. This paper describes the different domain adaptation steps that lowered our baseline absolute word error rate from 20.1% to 16.1%. These steps include the vocabulary selection, in order to include specific domain terms, language model adaptation, by interpolation of several different models, and acoustic model adaptation, using an unsupervised confidence based approach.