title: Gensim Word2Vec Training Data
body: <p>I am currently trying to train my own word2vec model with my own training data and I am utterly confused about the training data preprocessing.</p>
  <p>I ran a short script over my text which lemmatizes and also lower-cases the words in the text such that in the end my training data from a sentence (in German) like:</p>
  <p><code>&quot;Er hat heute zwei Birnen gegessen.&quot;</code></p>
  <p>the following comes out:</p>
  <p><code>[er, haben, heute, zwei, birne, essen] </code></p>
  <p>translated in English:</p>
  <p><code>He ate two pears today. </code></p>
  <p>results in:</p>
  <p><code>[he, eat, two, pear, today] </code></p>
  <p>Now the problem is: I haven't seen anyone do this to their training data. The words are kept in uppercase and also not lemmatized and I absolutely don't get how this works. Especially for German there are so many inflections of verbs. Should I just leave them that way? I don't understand how it works not doing the lemmatization since gensim doesn't even know which language it is trained on right?</p>
  <p>So in short: Should I do lemmatization and/or lowercasing or just leave every word as it is?</p>
  <p>Thanks a lot!</p>