In the generation step, a set of possible substitutions for the target word is commonly created by querying semantic databases such as Wordnet (Devlin and Tait, 1998) , learning substitution rules from sentence-aligned parallel corpora of complex-simple texts<cite> (Horn et al., 2014</cite>; Paetzold and Specia, 2017) , and learning word embeddings from a large corpora to obtain similar words of the complex word (Glavaš andŠtajner, 2015; Kim et al., 2016; Specia, 2016a, 2017) .