Investigating why BLEU penalizes non-statistical systems Eduard Hovy author 2007-sep 11 text Proceedings of the Workshop on Automatic procedures in MT evaluation Gregor Thurmair editor Khalid Choukri editor Bente Maegaard editor Copenhagen, Denmark conference publication hovy-2007-investigating https://aclanthology.org/2007.mtsummit-aptme.3/ 2007-sep 11