Many researchers have proposed greedy algorithms for estimating nonprobabilistic word-to-word translation models, also known as translation lexicons (e.g., Catizone, Russell, and Warwick 1989;Gale and Church 1991;Fung 1995;Kumano and Hirakawa 1994;Melamed 1995;Wu and Xia 1994).
so, the probability of a correct match for a rare word is proportional to the fraction of words around it that can be linked with higher confidence.