1. A machine translation decoding method comprising: receiving as input a text segment in a source language to be translated into a target language; generating an initial translation as an initial current target language translation; estimating a probability of correctness of the initial translation, the probability based on alignment links between words and phrases in the source language and words and phrases in the target language; applying one or more modification operators to the initial current target language translation by a computer to generate one or more modified target language translations; estimating a probability of correctness of the one or more modified target language translations, the probability based on alignment links between words and phrases in the source language and words and phrases in the target language; determining by the computer whether one or more of the modified target language translations represents an improved translation in comparison with the initial current target language translation by comparing the estimated probability of correctness of the initial translation with the estimated probability of correctness of the one or more modified target language translations; setting by the computer a modified target language translation with a higher probability based on the comparison as the modified current target language translation; and repeating said applying, said determining and said setting for the modified current target language translation until occurrence of a termination condition and outputting the modified current target language translation by the computer in response to the occurrence of the termination condition.