title: nltk frequency combining singular and plural, verb and adverb when tokenizing
body: <p>I want to count frequency but I want to combine singular and plural forms of nouns and verbs and their adverb forms. Excuse the poor sentence. For example: "That aggressive person walk by the house over there, one of many houses aggressively."</p>
  
  <p>Tokenize and count frequency</p>
  
  <pre><code>import nltk
  from nltk.tokenize import RegexpTokenizer
  test = "That aggressive person walk by the house over there, one of many houses aggressively"
  tokenizer = RegexpTokenizer(r'\w+')
  tokens = tokenizer.tokenize(test)
  fdist = nltk.FreqDist(tokens)
  common=fdist.most_common(100)
  </code></pre>
  
  <p>Output: 
  <code>[('houses', 1), ('aggressively', 1), ('by', 1), ('That', 1), ('house', 1), ('over', 1), ('there', 1), ('walk', 1), ('person', 1), ('many', 1), ('of', 1), ('aggressive', 1), ('one', 1), ('the', 1)]</code></p>
  
  <p>I want <code>house</code> and <code>houses</code> to be counted as <code>('house\houses', 2)</code> and <code>aggressive</code> and <code>aggressively</code> to be counted as <code>('aggressive\aggressively',2)</code>. Is this possible? If not, how do I proceed to make it look like that?</p>