title: Can't translate with babelfish
body: <p>so I'm trying to learn machine translation with nltk and babelfish, but I keep getting these errors whenever I try to use the babelfish methods:</p>
  
  <pre><code>&gt;&gt;&gt; import yahoo
  &gt;&gt;&gt; import nltk
  &gt;&gt;&gt; from nltk.misc import babelfish
  &gt;&gt;&gt; babelfish.translate('cookbook', 'english', 'spanish')
      Traceback (most recent call last):
      File "&lt;stdin&gt;", line 1, in &lt;module&gt;
      File "/usr/lib/python2.7/dist-packages/nltk/misc/babelfish.py", line 106, in  translate
      if not match: raise BabelfishChangedError("Can't recognize translated string.")
      nltk.misc.babelfish.BabelfishChangedError: Can't recognize translated string.
  &gt;&gt;&gt; for text in babelfish.babelize('cookbook', 'english', 'spanish'):
  ...   print text
  ... 
  cookbook
  Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  File "/usr/lib/python2.7/dist-packages/nltk/misc/babelfish.py", line 126, in babelize
  phrase = translate(phrase, next, flip[next])
  File "/usr/lib/python2.7/dist-packages/nltk/misc/babelfish.py", line 106, in translate
  if not match: raise BabelfishChangedError("Can't recognize translated string.")
  nltk.misc.babelfish.BabelfishChangedError: Can't recognize translated string.
  </code></pre>
  
  <p>What am I doing wrong here?</p>