A Structured Language Model Ciprian Chelba author 1997-07 text 35th Annual Meeting of the Association for Computational Linguistics and 8th Conference of the European Chapter of the Association for Computational Linguistics Association for Computational Linguistics Madrid, Spain conference publication chelba-1997-structured 10.3115/976909.979681 https://aclanthology.org/P97-1064/ 1997-07 498 500