By contrast, other aligners such as the Microsoft Bilingual Aligner (Moore, 2002), Hunalign (Varga et al., 2005) and Gargantua (Braune and Fraser, 2010) are autonomous and automatically infer a word-based translation lexicon from the texts being aligned as they proceed.
the performance of these methods degrades when the texts to be aligned are short as there is less data to support statistical inference of a bilingual lexicon.