  Speaker adaptation aims to estimate a speaker specific acoustic model from a
speaker independent one to minimize the mismatch between the training and
testing conditions arisen from speaker variabilities. A variety of neural
network adaptation methods have been proposed since deep learning models have
become the main stream. But there still lacks an experimental comparison
between different methods, especially when DNN-based acoustic models have been
advanced greatly. In this paper, we aim to close this gap by providing an
empirical evaluation of three typical speaker adaptation methods: LIN, LHUC and
KLD. Adaptation experiments, with different size of adaptation data, are
conducted on a strong TDNN-LSTM acoustic model. More challengingly, here, the
source and target we are concerned with are standard Mandarin speaker model and
accented Mandarin speaker model. We compare the performances of different
methods and their combinations. Speaker adaptation performance is also examined
by speaker's accent degree.
