DARPA ATIS Test Results June 1990 D S Pallett author W M Fisher author J G Fiscus author J S Garofolo author 1990 text Speech and Natural Language: Proceedings of a Workshop Held at Hidden Valley, Pennsylvania, June 24-27,1990 conference publication pallett-etal-1990-darpa https://aclanthology.org/H90-1024/ 1990