1. A method for domain specific normalization of a corpus of text, the method comprising: loading a corpus of text in memory of a computer; determining by a processor of the computer a domain for the corpus of text; retrieving from the memory of the computer by the processor of the computer a lexicon of replacement words for the determined domain, the lexicon comprising a set of source terms, at least one of the source terms being mapped to one of multiple different replacement terms having a complexity value aligned with an average complexity value for the multiple different replacement terms; and, text simplifying by the processor of the computer the corpus of text using the retrieved lexicon by replacing existing words in the corpus of text with the replacement words.