Neural network approaches have taken the field of natural language processing (NLP) by storm.
variants of long short-term memory (LSTM) networks (Hochreiter and Schmidhuber, 1997) have produced impressive results on some of the classic NLP tasks such as part-ofspeech tagging , syntactic parsing (Vinyals et al., 2015) and semantic role labeling (Zhou and Xu, 2015).