Rule-based and machine learning approaches for second language sentence-level readability Ildikó Pilán author Elena Volodina author Richard Johansson author 2014-06 text Proceedings of the Ninth Workshop on Innovative Use of NLP for Building Educational Applications Joel Tetreault editor Jill Burstein editor Claudia Leacock editor Association for Computational Linguistics Baltimore, Maryland conference publication pilan-etal-2014-rule 10.3115/v1/W14-1821 https://aclanthology.org/W14-1821/ 2014-06 174 184