A statistical MT tutorial workbook

---------------------------------------------------------------------------------- A Statistical MT Tutorial Workbook Kevin Knight prepared in connection with the JHU summer workshop April 30, 1999 ---------------------------------------------------------------------------------- 1. The Overall Plan We want to automatically analyze existing human sentence translations, with an eye toward building general translation rules -- we will use these rules to translate new texts automatically. I know this looks like a thick workbook, but if you take a day to work through it, you will know almost as much about statistical machine translation as anybody! The basic text that this tutorial relies on is Brown et al, “The Mathematics of Statistical Machine Translation”, Computational Linguistics, 1993. On top of this excellent presentation, I can only add some perspective and perhaps some sympathy for the poor reader, who has (after all) done nothing wrong. Important terms are underlined throughout! ---------------------------------------------------------------------------------- 2. Basic Probability We're going to consider that an English sentence e may translate into any French sentence f. Some translations are just more likely than others. Here are the basic notations we'll use to formalize “more likely”: P(e) -- a priori probability. The chance that e happens. For example, if e is the English string “I like snakes,” then ...