For the LM unit, instead of words we propose to adopt word-pronunciation pairs u = y, w .
given a phoneme sequence y l 1 = y 1 y 2 • • • y l as the input, the goal of our IM engine is to output a word sequenceŵ m 1 that maximizes the probability P (w, y l 1 ) as follows: where the concatenation of y i in each u i is equal to the input: In addition u j (j ≤ 0) are special symbols introduced to simplify the notation and u m+1 is a special symbol indicating a sentence boundary.