https://github.com/facebookresearch/fastText is a library for efficient learning of word representations and sentence classification
Discussion: https://news.ycombinator.com/item?id=12226988
Relevant papers:
Bag of Tricks for Efficient Text Classification: https://arxiv.org/abs/1607.01759v2
Enriching Word Vectors with Subword Information: https://arxiv.org/abs/1607.04606