Such tools are put to use by some of the existing systems (<cite>Krishna et al., 2016</cite>; Mittal, 2010 ) to obtain additional morphological or syntactic information about the sentences. This limits the scalability of <cite>those systems</cite>, as they cannot handle out of vocabulary words. Scalability of <cite>such systems</cite> is further restricted as the sentences often need to undergo linguistically involved preprocessing steps that lead to human in the loop processing.