It is often useful to reduce the vocabulary of a text by replacing words with common synonyms. By compressing the vocabulary without losing meaning, you can save memory in cases such as frequency analysis and text indexing. More details about these topics are available at https://en.wikipedia.org/wiki/Frequency_analysis and https://en.wikipedia.org/wiki/Full_text_search. Vocabulary reduction can also increase the occurrence of significant collocations, which was covered in the Discovering word collocations recipe of Chapter 1, Tokenizing Text and WordNet Basics.

class WordReplacer(object):
  def __init__(self, word_map):
    self.word_map...