The goal of transliteration model is to learn high-quality transliteration blocks from the training data in a unsupervised fashion.
a block X can be represented by its left and right boundaries in the source and target NEs shown in Figure 2: where f j+l j is the source letter-ngram with (l + 1) letters in source language, and its projection of e i +k i in the English NE with left boundary at the position of i, and right boundary at (i + k).